diff --git a/.github/FUNDING.yml b/.github/FUNDING.yml
new file mode 100644
index 000000000..13fadd222
--- /dev/null
+++ b/.github/FUNDING.yml
@@ -0,0 +1,3 @@
+# These are supported funding model platforms
+
+github: [mikepenz]
diff --git a/.travis.yml b/.travis.yml
index 8f6b451dc..fdfb61dd6 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -3,12 +3,12 @@ android:
   components:
     - tools
     - platform-tools
-    - build-tools-29.0.0
+    - build-tools-29.0.2
     - android-29
     - sys-img-armeabi-v7a-android-18
 before_install:
     - yes | sdkmanager "platforms;android-29"
-    - yes | sdkmanager "build-tools;29.0.0"
+    - yes | sdkmanager "build-tools;29.0.2"
 jdk:
     - oraclejdk8
 script:
diff --git a/README.md b/README.md
index d9927339b..2ac01ec8f 100644
--- a/README.md
+++ b/README.md
@@ -41,7 +41,7 @@ You can try it out here [Google Play](https://play.google.com/store/apps/details
 # Include in your project
 ## Latest releases
 
-- Kotlin | [v4.1.0](https://github.com/mikepenz/FastAdapter/tree/v4.1.0)
+- Kotlin | [v4.1.1](https://github.com/mikepenz/FastAdapter/tree/v4.1.1)
 - Java && AndroidX | [v3.3.1](https://github.com/mikepenz/FastAdapter/tree/v3.3.1)
 - Java && AppCompat | [v3.2.9](https://github.com/mikepenz/FastAdapter/tree/v3.2.9)
 
diff --git a/app/build.gradle b/app/build.gradle
index 175b21ca0..b99df8071 100644
--- a/app/build.gradle
+++ b/app/build.gradle
@@ -177,6 +177,6 @@ buildscript {
         jcenter()
     }
     dependencies {
-        classpath "io.realm:realm-gradle-plugin:5.11.0"
+        classpath "io.realm:realm-gradle-plugin:6.0.0"
     }
 }
\ No newline at end of file
diff --git a/app/src/main/java/com/mikepenz/fastadapter/app/AdvancedSampleActivity.kt b/app/src/main/java/com/mikepenz/fastadapter/app/AdvancedSampleActivity.kt
index 5d9dd60dc..ba0162e41 100644
--- a/app/src/main/java/com/mikepenz/fastadapter/app/AdvancedSampleActivity.kt
+++ b/app/src/main/java/com/mikepenz/fastadapter/app/AdvancedSampleActivity.kt
@@ -6,7 +6,6 @@ import android.view.MenuItem
 import android.view.View
 import androidx.appcompat.app.AppCompatActivity
 import androidx.appcompat.view.ActionMode
-import androidx.core.view.LayoutInflaterCompat
 import androidx.recyclerview.widget.DefaultItemAnimator
 import androidx.recyclerview.widget.LinearLayoutManager
 import androidx.recyclerview.widget.RecyclerView
@@ -21,7 +20,6 @@ import com.mikepenz.fastadapter.app.items.expandable.SimpleSubItem
 import com.mikepenz.fastadapter.expandable.getExpandableExtension
 import com.mikepenz.fastadapter.helpers.ActionModeHelper
 import com.mikepenz.fastadapter.select.getSelectExtension
-import com.mikepenz.iconics.context.IconicsLayoutInflater2
 import com.mikepenz.materialize.MaterializeBuilder
 import com.mikepenz.materialize.util.UIUtils
 import com.timehop.stickyheadersrecyclerview.StickyRecyclerHeadersDecoration
@@ -44,9 +42,6 @@ class AdvancedSampleActivity : AppCompatActivity() {
 
     override fun onCreate(savedInstanceState: Bundle?) {
         findViewById<View>(android.R.id.content).systemUiVisibility = findViewById<View>(android.R.id.content).systemUiVisibility or View.SYSTEM_UI_FLAG_LIGHT_STATUS_BAR
-        //as we use an icon from Android-Iconics via xml we add the IconicsLayoutInflater
-        //https://github.com/mikepenz/Android-Iconics
-        LayoutInflaterCompat.setFactory2(layoutInflater, IconicsLayoutInflater2(delegate))
         super.onCreate(savedInstanceState)
         setContentView(R.layout.activity_sample)
 
@@ -65,7 +60,7 @@ class AdvancedSampleActivity : AppCompatActivity() {
         //we also want the expandable feature
 
         //create our FastAdapter
-        val adapters: Collection<ItemAdapter<out GenericItem>> = Arrays.asList(mHeaderAdapter, mItemAdapter)
+        val adapters: Collection<ItemAdapter<out GenericItem>> = listOf(mHeaderAdapter, mItemAdapter)
         mFastAdapter = FastAdapter.with(adapters)
 
         mFastAdapter.getExpandableExtension()
@@ -85,7 +80,7 @@ class AdvancedSampleActivity : AppCompatActivity() {
 
         mFastAdapter.onPreLongClickListener = { _: View, _: GenericAdapter, item: GenericItem, position: Int ->
             //we do not want expandable items to be selected
-            if (item is IExpandable<*> && item.subItems != null) {
+            if (item is IExpandable<*> && item.subItems.isNotEmpty()) {
                 true
             } else {
                 //handle the longclick actions
diff --git a/app/src/main/java/com/mikepenz/fastadapter/app/EndlessScrollListActivity.kt b/app/src/main/java/com/mikepenz/fastadapter/app/EndlessScrollListActivity.kt
index b2feb30e9..f4b559296 100644
--- a/app/src/main/java/com/mikepenz/fastadapter/app/EndlessScrollListActivity.kt
+++ b/app/src/main/java/com/mikepenz/fastadapter/app/EndlessScrollListActivity.kt
@@ -78,7 +78,7 @@ class EndlessScrollListActivity : AppCompatActivity(), ItemTouchCallback, ItemFi
         fastItemAdapter.itemFilter.filterPredicate = { item: GenericItem, constraint: CharSequence? ->
             if (item is SimpleItem) {
                 //return true if we should filter it out
-                item.name?.text.toString().toLowerCase().contains(constraint.toString().toLowerCase())
+                item.name?.text.toString().contains(constraint.toString(), ignoreCase = true)
             } else {
                 //return false to keep it
                 false
diff --git a/app/src/main/java/com/mikepenz/fastadapter/app/ExpandableMultiselectDeleteSampleActivity.kt b/app/src/main/java/com/mikepenz/fastadapter/app/ExpandableMultiselectDeleteSampleActivity.kt
index 4c7db3323..7aa698e05 100644
--- a/app/src/main/java/com/mikepenz/fastadapter/app/ExpandableMultiselectDeleteSampleActivity.kt
+++ b/app/src/main/java/com/mikepenz/fastadapter/app/ExpandableMultiselectDeleteSampleActivity.kt
@@ -7,7 +7,6 @@ import android.view.View
 import android.widget.Toast
 import androidx.appcompat.app.AppCompatActivity
 import androidx.appcompat.view.ActionMode
-import androidx.core.view.LayoutInflaterCompat
 import androidx.recyclerview.widget.LinearLayoutManager
 import com.michaelflisar.dragselectrecyclerview.DragSelectTouchListener
 import com.mikepenz.fastadapter.*
@@ -22,7 +21,6 @@ import com.mikepenz.fastadapter.helpers.RangeSelectorHelper
 import com.mikepenz.fastadapter.select.SelectExtension
 import com.mikepenz.fastadapter.select.getSelectExtension
 import com.mikepenz.fastadapter.utils.SubItemUtil
-import com.mikepenz.iconics.context.IconicsLayoutInflater
 import com.mikepenz.itemanimators.SlideDownAlphaAnimator
 import com.mikepenz.materialize.MaterializeBuilder
 import com.mikepenz.materialize.util.UIUtils
@@ -40,9 +38,6 @@ class ExpandableMultiselectDeleteSampleActivity : AppCompatActivity() {
 
     override fun onCreate(savedInstanceState: Bundle?) {
         findViewById<View>(android.R.id.content).systemUiVisibility = findViewById<View>(android.R.id.content).systemUiVisibility or View.SYSTEM_UI_FLAG_LIGHT_STATUS_BAR
-        //as we use an icon from Android-Iconics via xml we add the IconicsLayoutInflater
-        //https://github.com/mikepenz/Android-Iconics
-        LayoutInflaterCompat.setFactory(layoutInflater, IconicsLayoutInflater(delegate))
         super.onCreate(savedInstanceState)
         setContentView(R.layout.activity_sample)
 
@@ -159,7 +154,7 @@ class ExpandableMultiselectDeleteSampleActivity : AppCompatActivity() {
         mExpandableExtension.expand()
 
         mSelectExtension.selectionListener = object : ISelectionListener<IItem<*>> {
-            override fun onSelectionChanged(item: IItem<*>?, selected: Boolean) {
+            override fun onSelectionChanged(item: IItem<*>, selected: Boolean) {
                 if (item is SimpleSubItem) {
                     val headerItem = item.parent
                     if (headerItem != null) {
@@ -213,7 +208,7 @@ class ExpandableMultiselectDeleteSampleActivity : AppCompatActivity() {
 
             // delete the selected items with the SubItemUtil to correctly handle sub items
             // this will even delete empty headers if you want to
-            SubItemUtil.deleteSelected(fastItemAdapter, mSelectExtension, mExpandableExtension, true, true)
+            SubItemUtil.deleteSelected(fastItemAdapter, mSelectExtension, mExpandableExtension, notifyParent = true, deleteEmptyHeaders = true)
             //as we no longer have a selection so the actionMode can be finished
             mode.finish()
             //we consume the event
diff --git a/app/src/main/java/com/mikepenz/fastadapter/app/ExpandableSampleActivity.kt b/app/src/main/java/com/mikepenz/fastadapter/app/ExpandableSampleActivity.kt
index dab8d6ac9..579f6614d 100755
--- a/app/src/main/java/com/mikepenz/fastadapter/app/ExpandableSampleActivity.kt
+++ b/app/src/main/java/com/mikepenz/fastadapter/app/ExpandableSampleActivity.kt
@@ -4,7 +4,6 @@ import android.os.Bundle
 import android.view.MenuItem
 import android.view.View
 import androidx.appcompat.app.AppCompatActivity
-import androidx.core.view.LayoutInflaterCompat
 import androidx.recyclerview.widget.LinearLayoutManager
 import com.mikepenz.fastadapter.GenericItem
 import com.mikepenz.fastadapter.adapters.FastItemAdapter
@@ -13,7 +12,6 @@ import com.mikepenz.fastadapter.app.items.expandable.SimpleSubExpandableItem
 import com.mikepenz.fastadapter.app.items.expandable.SimpleSubItem
 import com.mikepenz.fastadapter.expandable.getExpandableExtension
 import com.mikepenz.fastadapter.select.getSelectExtension
-import com.mikepenz.iconics.context.IconicsLayoutInflater2
 import com.mikepenz.itemanimators.SlideDownAlphaAnimator
 import com.mikepenz.materialize.MaterializeBuilder
 import kotlinx.android.synthetic.main.activity_sample.*
@@ -26,9 +24,6 @@ class ExpandableSampleActivity : AppCompatActivity() {
 
     override fun onCreate(savedInstanceState: Bundle?) {
         findViewById<View>(android.R.id.content).systemUiVisibility = findViewById<View>(android.R.id.content).systemUiVisibility or View.SYSTEM_UI_FLAG_LIGHT_STATUS_BAR
-        //as we use an icon from Android-Iconics via xml we add the IconicsLayoutInflater
-        //https://github.com/mikepenz/Android-Iconics
-        LayoutInflaterCompat.setFactory2(layoutInflater, IconicsLayoutInflater2(delegate))
         super.onCreate(savedInstanceState)
         setContentView(R.layout.activity_sample)
 
diff --git a/app/src/main/java/com/mikepenz/fastadapter/app/IconGridActivity.kt b/app/src/main/java/com/mikepenz/fastadapter/app/IconGridActivity.kt
index c2eedc90c..2cc874c39 100644
--- a/app/src/main/java/com/mikepenz/fastadapter/app/IconGridActivity.kt
+++ b/app/src/main/java/com/mikepenz/fastadapter/app/IconGridActivity.kt
@@ -4,7 +4,6 @@ import android.os.Bundle
 import android.view.MenuItem
 import android.view.View
 import androidx.appcompat.app.AppCompatActivity
-import androidx.core.view.LayoutInflaterCompat
 import androidx.recyclerview.widget.GridLayoutManager
 import com.mikepenz.fastadapter.adapters.FastItemAdapter
 import com.mikepenz.fastadapter.adapters.GenericFastItemAdapter
@@ -12,7 +11,6 @@ import com.mikepenz.fastadapter.app.items.IconItem
 import com.mikepenz.fastadapter.app.items.expandable.SimpleSubExpandableItem
 import com.mikepenz.fastadapter.expandable.getExpandableExtension
 import com.mikepenz.iconics.Iconics
-import com.mikepenz.iconics.context.IconicsLayoutInflater2
 import com.mikepenz.itemanimators.SlideDownAlphaAnimator
 import com.mikepenz.materialize.MaterializeBuilder
 import kotlinx.android.synthetic.main.activity_sample.*
@@ -25,9 +23,6 @@ class IconGridActivity : AppCompatActivity() {
 
     override fun onCreate(savedInstanceState: Bundle?) {
         findViewById<View>(android.R.id.content).systemUiVisibility = findViewById<View>(android.R.id.content).systemUiVisibility or View.SYSTEM_UI_FLAG_LIGHT_STATUS_BAR
-        //as we use an icon from Android-Iconics via xml we add the IconicsLayoutInflater
-        //https://github.com/mikepenz/Android-Iconics
-        LayoutInflaterCompat.setFactory2(layoutInflater, IconicsLayoutInflater2(delegate))
 
         super.onCreate(savedInstanceState)
         setContentView(R.layout.activity_sample)
diff --git a/app/src/main/java/com/mikepenz/fastadapter/app/ModelItemActivity.kt b/app/src/main/java/com/mikepenz/fastadapter/app/ModelItemActivity.kt
index 38dc8452d..08db80329 100644
--- a/app/src/main/java/com/mikepenz/fastadapter/app/ModelItemActivity.kt
+++ b/app/src/main/java/com/mikepenz/fastadapter/app/ModelItemActivity.kt
@@ -17,9 +17,9 @@ import com.mikepenz.itemanimators.SlideDownAlphaAnimator
 import com.mikepenz.materialize.MaterializeBuilder
 import com.turingtechnologies.materialscrollbar.CustomIndicator
 import com.turingtechnologies.materialscrollbar.DragScrollBar
-import kotlinx.android.synthetic.main.activity_sample.*
+import kotlinx.android.synthetic.main.activity_sample.rv
+import kotlinx.android.synthetic.main.activity_sample.toolbar
 import java.util.ArrayList
-import java.util.Arrays
 import kotlin.Comparator
 
 class ModelItemActivity : AppCompatActivity() {
@@ -45,7 +45,7 @@ class ModelItemActivity : AppCompatActivity() {
         }
 
         //create our FastAdapter which will manage everything
-        fastAdapter = FastAdapter.with(Arrays.asList(itemAdapter))
+        fastAdapter = FastAdapter.with(listOf(itemAdapter))
         val selectExtension = fastAdapter.getSelectExtension()
         selectExtension.isSelectable = true
 
diff --git a/app/src/main/java/com/mikepenz/fastadapter/app/MultiTypeModelItemActivity.kt b/app/src/main/java/com/mikepenz/fastadapter/app/MultiTypeModelItemActivity.kt
index 679f22175..5fae6bf86 100644
--- a/app/src/main/java/com/mikepenz/fastadapter/app/MultiTypeModelItemActivity.kt
+++ b/app/src/main/java/com/mikepenz/fastadapter/app/MultiTypeModelItemActivity.kt
@@ -45,7 +45,7 @@ class MultiTypeModelItemActivity : AppCompatActivity() {
         }
 
         //create our FastAdapter which will manage everything
-        fastAdapter = FastAdapter.with(Arrays.asList(itemAdapter))
+        fastAdapter = FastAdapter.with(listOf(itemAdapter))
         val selectExtension = fastAdapter.getSelectExtension()
         selectExtension.isSelectable = true
 
diff --git a/app/src/main/java/com/mikepenz/fastadapter/app/MultiselectSampleActivity.kt b/app/src/main/java/com/mikepenz/fastadapter/app/MultiselectSampleActivity.kt
index 0e0c61f35..89b72644b 100755
--- a/app/src/main/java/com/mikepenz/fastadapter/app/MultiselectSampleActivity.kt
+++ b/app/src/main/java/com/mikepenz/fastadapter/app/MultiselectSampleActivity.kt
@@ -62,7 +62,7 @@ class MultiselectSampleActivity : AppCompatActivity() {
             multiSelect = true
             selectOnLongClick = true
             selectionListener = object : ISelectionListener<SimpleItem> {
-                override fun onSelectionChanged(item: SimpleItem?, selected: Boolean) {
+                override fun onSelectionChanged(item: SimpleItem, selected: Boolean) {
                     Log.i("FastAdapter", "SelectedCount: " + selectExtension.selections.size + " ItemsCount: " + selectExtension.selectedItems.size)
                 }
             }
diff --git a/app/src/main/java/com/mikepenz/fastadapter/app/RealmActivity.kt b/app/src/main/java/com/mikepenz/fastadapter/app/RealmActivity.kt
index c259c69ab..a8a70d0d5 100755
--- a/app/src/main/java/com/mikepenz/fastadapter/app/RealmActivity.kt
+++ b/app/src/main/java/com/mikepenz/fastadapter/app/RealmActivity.kt
@@ -45,9 +45,7 @@ class RealmActivity : AppCompatActivity() {
 
         //configure our fastAdapter
         mFastItemAdapter.onClickListener = { v: View?, _: IAdapter<RealmSampleUserItem>, item: RealmSampleUserItem, _: Int ->
-            v?.let { v ->
-                Toast.makeText(v.context, item.name, Toast.LENGTH_SHORT).show()
-            }
+            v?.let { Toast.makeText(it.context, item.name, Toast.LENGTH_SHORT).show() }
             false
         }
 
diff --git a/app/src/main/java/com/mikepenz/fastadapter/app/SortActivity.kt b/app/src/main/java/com/mikepenz/fastadapter/app/SortActivity.kt
index 21cc0edc5..169470b56 100644
--- a/app/src/main/java/com/mikepenz/fastadapter/app/SortActivity.kt
+++ b/app/src/main/java/com/mikepenz/fastadapter/app/SortActivity.kt
@@ -24,10 +24,8 @@ import com.mikepenz.iconics.IconicsColor
 import com.mikepenz.iconics.IconicsDrawable
 import com.mikepenz.iconics.typeface.library.materialdesigniconic.MaterialDesignIconic
 import com.mikepenz.materialize.MaterializeBuilder
-import kotlinx.android.synthetic.main.activity_sort.*
+import kotlinx.android.synthetic.main.activity_sort.toolbar
 import java.io.Serializable
-import java.lang.annotation.Retention
-import java.lang.annotation.RetentionPolicy
 import java.util.*
 
 /**
@@ -128,7 +126,6 @@ class SortActivity : AppCompatActivity() {
         super.onSaveInstanceState(outState)
     }
 
-
     override fun onCreateOptionsMenu(menu: Menu): Boolean {
         val inflater = menuInflater
         inflater.inflate(R.menu.sort, menu)
@@ -216,7 +213,7 @@ class SortActivity : AppCompatActivity() {
         return result.withDescription("$description letter in the alphabet")
     }
 
-    @Retention(RetentionPolicy.SOURCE)
+    @Retention(AnnotationRetention.SOURCE)
     @IntDef(SORT_NONE, SORT_ASCENDING, SORT_DESCENDING)
     annotation class SortingStrategy
 
diff --git a/app/src/main/java/com/mikepenz/fastadapter/app/SwipeListActivity.kt b/app/src/main/java/com/mikepenz/fastadapter/app/SwipeListActivity.kt
index 9d29408f9..08da31e11 100644
--- a/app/src/main/java/com/mikepenz/fastadapter/app/SwipeListActivity.kt
+++ b/app/src/main/java/com/mikepenz/fastadapter/app/SwipeListActivity.kt
@@ -76,7 +76,7 @@ class SwipeListActivity : AppCompatActivity(), ItemTouchCallback, SimpleSwipeCal
 
         //configure the itemAdapter
         fastItemAdapter.itemFilter.filterPredicate = { item: SwipeableItem, constraint: CharSequence? ->
-            item.name?.text.toString().toLowerCase().contains(constraint.toString().toLowerCase())
+            item.name?.text.toString().contains(constraint.toString(), ignoreCase = true)
         }
 
         //get our recyclerView and do basic setup
diff --git a/app/src/main/java/com/mikepenz/fastadapter/app/adapters/FastScrollIndicatorAdapter.kt b/app/src/main/java/com/mikepenz/fastadapter/app/adapters/FastScrollIndicatorAdapter.kt
index 8a4dcabe3..20894411f 100644
--- a/app/src/main/java/com/mikepenz/fastadapter/app/adapters/FastScrollIndicatorAdapter.kt
+++ b/app/src/main/java/com/mikepenz/fastadapter/app/adapters/FastScrollIndicatorAdapter.kt
@@ -35,7 +35,7 @@ class FastScrollIndicatorAdapter<Item : GenericItem> : RecyclerView.Adapter<Recy
 
     override fun getCustomStringForElement(position: Int): String {
         val item = getItem(position)
-        return if (item is ModelIconItem && item.model.icon.name != null) {
+        return if (item is ModelIconItem && item.model.icon.name.isNotEmpty()) {
             //based on the position we set the headers text
             item.model.icon.name
         } else ""
diff --git a/app/src/main/java/com/mikepenz/fastadapter/app/dummy/ImageDummyData.kt b/app/src/main/java/com/mikepenz/fastadapter/app/dummy/ImageDummyData.kt
index e574418ef..6bfdb05f7 100644
--- a/app/src/main/java/com/mikepenz/fastadapter/app/dummy/ImageDummyData.kt
+++ b/app/src/main/java/com/mikepenz/fastadapter/app/dummy/ImageDummyData.kt
@@ -90,10 +90,10 @@ object ImageDummyData {
         )
 
     private fun toList(vararg imageItems: ImageItem): List<ImageItem> {
-        return listOf(*imageItems)
+        return imageItems.toList()
     }
 
     private fun toList(vararg imageItems: SimpleImageItem): List<SimpleImageItem> {
-        return listOf(*imageItems)
+        return imageItems.toList()
     }
 }
diff --git a/app/src/main/java/com/mikepenz/fastadapter/app/items/HeaderSelectionItem.kt b/app/src/main/java/com/mikepenz/fastadapter/app/items/HeaderSelectionItem.kt
index 909c6681a..7ae5aae25 100644
--- a/app/src/main/java/com/mikepenz/fastadapter/app/items/HeaderSelectionItem.kt
+++ b/app/src/main/java/com/mikepenz/fastadapter/app/items/HeaderSelectionItem.kt
@@ -18,17 +18,17 @@ open class HeaderSelectionItem : SimpleSubExpandableItem() {
         this.mSubSelectionProvider = subSelectionProvider
     }
 
-    override fun bindView(viewHolder: ViewHolder, payloads: MutableList<Any>) {
-        super.bindView(viewHolder, payloads)
+    override fun bindView(holder: ViewHolder, payloads: MutableList<Any>) {
+        super.bindView(holder, payloads)
 
         //get the context
-        val ctx = viewHolder.itemView.context
+        val ctx = holder.itemView.context
 
         //set the background for the item
-        viewHolder.view.clearAnimation()
-        ViewCompat.setBackground(viewHolder.view, FastAdapterUIUtils.getSelectableBackground(ctx, Color.RED, true))
+        holder.view.clearAnimation()
+        ViewCompat.setBackground(holder.view, FastAdapterUIUtils.getSelectableBackground(ctx, Color.RED, true))
         //set the text for the name
-        StringHolder.applyTo(name, viewHolder.name)
+        StringHolder.applyTo(name, holder.name)
         //set the text for the description or hide
 
         var selectedSubItems = 0
@@ -37,8 +37,8 @@ open class HeaderSelectionItem : SimpleSubExpandableItem() {
         val descr = StringHolder(description?.text)
         if (selectedSubItems > 0)
             descr.setText("Selected children: " + selectedSubItems + "/" + subItems.size)
-        StringHolder.applyToOrHide(descr, viewHolder.description)
+        StringHolder.applyToOrHide(descr, holder.description)
 
-        viewHolder.description.setTextColor(if (selectedSubItems == 0) Color.BLACK else Color.RED)
+        holder.description.setTextColor(if (selectedSubItems == 0) Color.BLACK else Color.RED)
     }
 }
diff --git a/app/src/main/java/com/mikepenz/fastadapter/app/items/IconItem.kt b/app/src/main/java/com/mikepenz/fastadapter/app/items/IconItem.kt
index 36f8288bf..b81794503 100644
--- a/app/src/main/java/com/mikepenz/fastadapter/app/items/IconItem.kt
+++ b/app/src/main/java/com/mikepenz/fastadapter/app/items/IconItem.kt
@@ -23,7 +23,7 @@ class IconItem : AbstractItem<IconItem.ViewHolder>(), IExpandable<IconItem.ViewH
 
     override var subItems: MutableList<ISubItem<*>>
         get() = mutableListOf()
-        set(list) {
+        set(_) {
         }
 
     override val isAutoExpanding: Boolean
@@ -83,7 +83,7 @@ class IconItem : AbstractItem<IconItem.ViewHolder>(), IExpandable<IconItem.ViewH
     /**
      * our ViewHolder
      */
-    class ViewHolder(protected var view: View) : RecyclerView.ViewHolder(view) {
+    class ViewHolder(var view: View) : RecyclerView.ViewHolder(view) {
         var name: TextView = view.findViewById(R.id.name)
         var image: IconicsImageView = view.findViewById(R.id.icon)
     }
diff --git a/app/src/main/java/com/mikepenz/fastadapter/app/items/ImageItem.kt b/app/src/main/java/com/mikepenz/fastadapter/app/items/ImageItem.kt
index 4034700c5..b221196f1 100644
--- a/app/src/main/java/com/mikepenz/fastadapter/app/items/ImageItem.kt
+++ b/app/src/main/java/com/mikepenz/fastadapter/app/items/ImageItem.kt
@@ -12,7 +12,6 @@ import com.mikepenz.fastadapter.app.R
 import com.mikepenz.fastadapter.items.AbstractItem
 import com.mikepenz.fastadapter.listeners.ClickEventHook
 import com.mikepenz.iconics.view.IconicsImageView
-import java.util.*
 
 /**
  * Created by mikepenz on 28.12.15.
@@ -68,25 +67,25 @@ class ImageItem : AbstractItem<ImageItem.ViewHolder>() {
     /**
      * binds the data of this item onto the viewHolder
      *
-     * @param viewHolder the viewHolder of this item
+     * @param holder the viewHolder of this item
      */
-    override fun bindView(viewHolder: ViewHolder, payloads: MutableList<Any>) {
-        super.bindView(viewHolder, payloads)
+    override fun bindView(holder: ViewHolder, payloads: MutableList<Any>) {
+        super.bindView(holder, payloads)
 
         //get the context
-        val ctx = viewHolder.itemView.context
+        val ctx = holder.itemView.context
 
         //define our data for the view
-        viewHolder.imageName.text = mName
-        viewHolder.imageDescription.text = mDescription
-        viewHolder.imageView.setImageBitmap(null)
+        holder.imageName.text = mName
+        holder.imageDescription.text = mDescription
+        holder.imageView.setImageBitmap(null)
 
         //we pre-style our heart :D
-        style(viewHolder.imageLovedOn, if (mStarred) 1 else 0)
-        style(viewHolder.imageLovedOff, if (mStarred) 0 else 1)
+        style(holder.imageLovedOn, if (mStarred) 1 else 0)
+        style(holder.imageLovedOff, if (mStarred) 0 else 1)
 
         //load glide
-        Glide.with(ctx).load(mImageUrl).animate(R.anim.alpha_on).into(viewHolder.imageView)
+        Glide.with(ctx).load(mImageUrl).animate(R.anim.alpha_on).into(holder.imageView)
     }
 
     override fun unbindView(holder: ViewHolder) {
@@ -129,7 +128,7 @@ class ImageItem : AbstractItem<ImageItem.ViewHolder>() {
     /**
      * our ViewHolder
      */
-    class ViewHolder(protected var view: View) : RecyclerView.ViewHolder(view) {
+    class ViewHolder(var view: View) : RecyclerView.ViewHolder(view) {
         var imageView: ImageView = view.findViewById(R.id.item_image_img)
         var imageName: TextView = view.findViewById(R.id.item_image_name)
         var imageDescription: TextView = view.findViewById(R.id.item_image_description)
diff --git a/app/src/main/java/com/mikepenz/fastadapter/app/items/RadioButtonSampleItem.kt b/app/src/main/java/com/mikepenz/fastadapter/app/items/RadioButtonSampleItem.kt
index a529fdfd6..e9726ab75 100644
--- a/app/src/main/java/com/mikepenz/fastadapter/app/items/RadioButtonSampleItem.kt
+++ b/app/src/main/java/com/mikepenz/fastadapter/app/items/RadioButtonSampleItem.kt
@@ -91,7 +91,7 @@ class RadioButtonSampleItem : AbstractItem<RadioButtonSampleItem.ViewHolder>() {
     /**
      * our ViewHolder
      */
-    class ViewHolder(protected var view: View) : RecyclerView.ViewHolder(view) {
+    class ViewHolder(var view: View) : RecyclerView.ViewHolder(view) {
         var radioButton: RadioButton = view.findViewById(R.id.radiobutton)
         internal var name: TextView = view.findViewById(R.id.material_drawer_name)
         internal var description: TextView = view.findViewById(R.id.material_drawer_description)
diff --git a/app/src/main/java/com/mikepenz/fastadapter/app/items/RealmSampleUserItem.kt b/app/src/main/java/com/mikepenz/fastadapter/app/items/RealmSampleUserItem.kt
index 4cbb3cc90..38842a7dd 100644
--- a/app/src/main/java/com/mikepenz/fastadapter/app/items/RealmSampleUserItem.kt
+++ b/app/src/main/java/com/mikepenz/fastadapter/app/items/RealmSampleUserItem.kt
@@ -223,9 +223,7 @@ open class RealmSampleUserItem : RealmObject(), IItem<RealmSampleUserItem.ViewHo
      *
      * @return
      */
-    override fun hashCode(): Int {
-        return java.lang.Long.valueOf(identifier).hashCode()
-    }
+    override fun hashCode(): Int = identifier.hashCode()
 
     class ViewHolder(view: View) : RecyclerView.ViewHolder(view) {
         var name: TextView = view.findViewById<View>(R.id.text) as TextView
diff --git a/app/src/main/java/com/mikepenz/fastadapter/app/items/expandable/SimpleSubExpandableItem.kt b/app/src/main/java/com/mikepenz/fastadapter/app/items/expandable/SimpleSubExpandableItem.kt
index 8f6cefe28..6618a2bae 100644
--- a/app/src/main/java/com/mikepenz/fastadapter/app/items/expandable/SimpleSubExpandableItem.kt
+++ b/app/src/main/java/com/mikepenz/fastadapter/app/items/expandable/SimpleSubExpandableItem.kt
@@ -7,6 +7,7 @@ import android.widget.TextView
 import androidx.annotation.StringRes
 import androidx.core.view.ViewCompat
 import androidx.recyclerview.widget.RecyclerView
+import com.mikepenz.fastadapter.ClickListener
 import com.mikepenz.fastadapter.IAdapter
 import com.mikepenz.fastadapter.IClickable
 import com.mikepenz.fastadapter.ISubItem
@@ -24,7 +25,7 @@ open class SimpleSubExpandableItem : AbstractExpandableItem<SimpleSubExpandableI
     var name: StringHolder? = null
     var description: StringHolder? = null
 
-    private var mOnClickListener: ((v: View?, adapter: IAdapter<SimpleSubExpandableItem>, item: SimpleSubExpandableItem, position: Int) -> Boolean)? = null
+    private var mOnClickListener: ClickListener<SimpleSubExpandableItem>? = null
 
     //we define a clickListener in here so we can directly animate
     /**
@@ -33,8 +34,8 @@ open class SimpleSubExpandableItem : AbstractExpandableItem<SimpleSubExpandableI
      * @return
      */
     @Suppress("SetterBackingFieldAssignment")
-    override var onItemClickListener: ((v: View?, adapter: IAdapter<SimpleSubExpandableItem>, item: SimpleSubExpandableItem, position: Int) -> Boolean)? = { v: View?, adapter: IAdapter<SimpleSubExpandableItem>, item: SimpleSubExpandableItem, position: Int ->
-        if (item.subItems != null) {
+    override var onItemClickListener: ClickListener<SimpleSubExpandableItem>? = { v: View?, adapter: IAdapter<SimpleSubExpandableItem>, item: SimpleSubExpandableItem, position: Int ->
+        if (item.subItems.isNotEmpty()) {
             v?.findViewById<View>(R.id.material_drawer_icon)?.let {
                 if (!item.isExpanded) {
                     ViewCompat.animate(it).rotation(180f).start()
@@ -49,14 +50,13 @@ open class SimpleSubExpandableItem : AbstractExpandableItem<SimpleSubExpandableI
             this.mOnClickListener = onClickListener // on purpose
         }
 
-    override var onPreItemClickListener: ((v: View?, adapter: IAdapter<SimpleSubExpandableItem>, item: SimpleSubExpandableItem, position: Int) -> Boolean)?
+    override var onPreItemClickListener: ClickListener<SimpleSubExpandableItem>?
         get() = null
-        set(onClickListener) {
-        }
+        set(_) {}
 
-    override//this might not be true for your application
-    var isSelectable: Boolean
-        get() = subItems == null
+    //this might not be true for your application
+    override var isSelectable: Boolean
+        get() = subItems.isEmpty()
         set(value) {
             super.isSelectable = value
         }
@@ -121,7 +121,7 @@ open class SimpleSubExpandableItem : AbstractExpandableItem<SimpleSubExpandableI
         //set the text for the description or hide
         StringHolder.applyToOrHide(description, holder.description)
 
-        if (subItems == null || subItems.size == 0) {
+        if (subItems.isEmpty()) {
             holder.icon.visibility = View.GONE
         } else {
             holder.icon.visibility = View.VISIBLE
diff --git a/app/src/main/java/com/mikepenz/fastadapter/app/model/ModelIconItem.kt b/app/src/main/java/com/mikepenz/fastadapter/app/model/ModelIconItem.kt
index 977e24a3a..103a59902 100644
--- a/app/src/main/java/com/mikepenz/fastadapter/app/model/ModelIconItem.kt
+++ b/app/src/main/java/com/mikepenz/fastadapter/app/model/ModelIconItem.kt
@@ -55,7 +55,7 @@ open class ModelIconItem(icon: IconModel) : ModelAbstractItem<IconModel, ModelIc
     /**
      * our ViewHolder
      */
-    class ViewHolder(protected var view: View) : RecyclerView.ViewHolder(view) {
+    class ViewHolder(val view: View) : RecyclerView.ViewHolder(view) {
         var name: TextView = view.findViewById(R.id.name)
         var image: IconicsImageView = view.findViewById(R.id.icon)
     }
diff --git a/app/src/main/java/com/mikepenz/fastadapter/app/paged/DemoEntity.kt b/app/src/main/java/com/mikepenz/fastadapter/app/paged/DemoEntity.kt
index 8dd7c20de..c117fbc13 100644
--- a/app/src/main/java/com/mikepenz/fastadapter/app/paged/DemoEntity.kt
+++ b/app/src/main/java/com/mikepenz/fastadapter/app/paged/DemoEntity.kt
@@ -23,10 +23,10 @@ class DemoEntity {
     }
 
 
-    override fun equals(obj: Any?): Boolean {
-        if (obj === this)
+    override fun equals(other: Any?): Boolean {
+        if (other === this)
             return true
-        val demoEntity = obj as DemoEntity?
+        val demoEntity = other as DemoEntity?
         return demoEntity!!.identifier == this.identifier &&
                 demoEntity.data1 === demoEntity.data1 &&
                 demoEntity.data2 === demoEntity.data2
diff --git a/app/src/main/java/com/mikepenz/fastadapter/app/paged/DemoEntityDataSource.kt b/app/src/main/java/com/mikepenz/fastadapter/app/paged/DemoEntityDataSource.kt
index 50b983e15..754bd92a8 100644
--- a/app/src/main/java/com/mikepenz/fastadapter/app/paged/DemoEntityDataSource.kt
+++ b/app/src/main/java/com/mikepenz/fastadapter/app/paged/DemoEntityDataSource.kt
@@ -11,8 +11,8 @@ class DemoEntityDataSource(ctx: Context) : PageKeyedDataSource<Int, DemoEntity>(
     private val demoEntityDAO: DemoEntityLocalDAO = LocalRepository.getDemoEntityDB(ctx).demoEntityDAO()
 
     //is called too load initial data
-    override fun loadInitial(params: PageKeyedDataSource.LoadInitialParams<Int>,
-                             callback: PageKeyedDataSource.LoadInitialCallback<Int, DemoEntity>) {
+    override fun loadInitial(params: LoadInitialParams<Int>,
+                             callback: LoadInitialCallback<Int, DemoEntity>) {
 
         var cpns = demoEntityDAO.getDemoEntitiesBySize(0, params.requestedLoadSize)
 
@@ -34,11 +34,11 @@ class DemoEntityDataSource(ctx: Context) : PageKeyedDataSource<Int, DemoEntity>(
         callback.onResult(cpns, null, cpns.size + 1)
     }
 
-    override fun loadBefore(params: PageKeyedDataSource.LoadParams<Int>, callback: PageKeyedDataSource.LoadCallback<Int, DemoEntity>) {
+    override fun loadBefore(params: LoadParams<Int>, callback: LoadCallback<Int, DemoEntity>) {
     }
 
     //is called to load pages of data using key passed in params
-    override fun loadAfter(params: PageKeyedDataSource.LoadParams<Int>, callback: PageKeyedDataSource.LoadCallback<Int, DemoEntity>) {
+    override fun loadAfter(params: LoadParams<Int>, callback: LoadCallback<Int, DemoEntity>) {
         val cpns = demoEntityDAO.getDemoEntitiesBySize(params.key, params.requestedLoadSize)
 
         Thread.sleep(500)
diff --git a/app/src/main/res/layout/expandable_item.xml b/app/src/main/res/layout/expandable_item.xml
index b5ee1cb6c..b8e5a1638 100755
--- a/app/src/main/res/layout/expandable_item.xml
+++ b/app/src/main/res/layout/expandable_item.xml
@@ -5,10 +5,10 @@
     android:layout_width="match_parent"
     android:layout_height="@dimen/material_drawer_item_primary"
     android:orientation="horizontal"
-    android:paddingEnd="@dimen/material_drawer_vertical_padding"
+    android:paddingStart="@dimen/material_drawer_vertical_padding"
     android:paddingLeft="@dimen/material_drawer_vertical_padding"
-    android:paddingRight="@dimen/material_drawer_vertical_padding"
-    android:paddingStart="@dimen/material_drawer_vertical_padding">
+    android:paddingEnd="@dimen/material_drawer_vertical_padding"
+    android:paddingRight="@dimen/material_drawer_vertical_padding">
 
     <LinearLayout
         android:layout_width="0dp"
@@ -42,12 +42,12 @@
             tools:text="Some drawer text" />
     </LinearLayout>
 
-    <ImageView
+    <com.mikepenz.iconics.view.IconicsImageView
         android:id="@+id/material_drawer_icon"
         android:layout_width="16dp"
         android:layout_height="16dp"
         android:layout_marginTop="@dimen/material_drawer_vertical_padding"
-        app:ico_color="@color/md_black_1000"
-        app:ico_icon="gmd-keyboard-arrow-up"
-        app:ico_size="16dp" />
+        app:iiv_color="@color/md_black_1000"
+        app:iiv_icon="gmd-keyboard-arrow-up"
+        app:iiv_size="16dp" />
 </LinearLayout>
diff --git a/build.gradle b/build.gradle
index 39d929bb8..d38bc51ca 100644
--- a/build.gradle
+++ b/build.gradle
@@ -2,8 +2,8 @@
 buildscript {
     ext {
         release = [
-                versionName: "4.1.0",
-                versionCode: 4100
+                versionName: "4.1.1",
+                versionCode: 4101
         ]
 
         setup = [
@@ -15,17 +15,17 @@ buildscript {
 
         versions = [
                 androidX        : '1.0.0',
-                recyclerView    : '1.1.0-beta04',
-                material        : '1.1.0-alpha10',
+                recyclerView    : '1.1.0-beta05',
+                material        : '1.1.0-beta02',
                 appcompat       : '1.1.0',
                 drawerlayout    : '1.1.0-alpha03',
-                constraintLayout: '2.0.0-beta2',
+                constraintLayout: '2.0.0-beta3',
                 cardview        : '1.0.0',
                 kotlin          : '1.3.50',
                 materialize     : '1.2.1',
-                iconics         : '4.0.0',
-                materialdrawer  : '7.0.0-rc07',
-                aboutlib        : '7.0.1',
+                iconics         : '4.0.1',
+                materialdrawer  : '7.0.0-rc08',
+                aboutlib        : '7.0.4',
                 roboelectric    : '4.3',
                 detekt          : '1.0.1',
                 paging          : "2.1.0",
diff --git a/library-core/src/main/java/com/mikepenz/fastadapter/FastAdapter.kt b/library-core/src/main/java/com/mikepenz/fastadapter/FastAdapter.kt
index d834022c2..44dc70af3 100644
--- a/library-core/src/main/java/com/mikepenz/fastadapter/FastAdapter.kt
+++ b/library-core/src/main/java/com/mikepenz/fastadapter/FastAdapter.kt
@@ -35,7 +35,7 @@ typealias GenericFastAdapter = FastAdapter<GenericItem>
  *
  * See the sample application for more details
  *
- * @param <Item> Defines the type of items this `FastAdapter` manages (in case of multiple different types, use `IItem`)</Item>
+ * @param Item Defines the type of items this `FastAdapter` manages (in case of multiple different types, use `IItem`)
  */
 @FastAdapterDsl
 open class FastAdapter<Item : GenericItem> : RecyclerView.Adapter<RecyclerView.ViewHolder>() {
@@ -80,17 +80,21 @@ open class FastAdapter<Item : GenericItem> : RecyclerView.Adapter<RecyclerView.V
     // if set to `false` will not attach any listeners to the list. click events will have to be handled manually
     var attachDefaultListeners = true
 
+    private val logger = VerboseLogger(TAG)
+
     /**
      * enables the verbose log for the adapter
      **/
-    var verboseLoggingEnabled = false
+    var verboseLoggingEnabled: Boolean
+        get() = logger.isEnabled
+        set(value) { logger.isEnabled = value }
 
     // the listeners which can be hooked on an item
     var onPreClickListener: ClickListener<Item>? = null
     var onClickListener: ClickListener<Item>? = null
-    var onPreLongClickListener: ((v: View, adapter: IAdapter<Item>, item: Item, position: Int) -> Boolean)? = null
-    var onLongClickListener: ((v: View, adapter: IAdapter<Item>, item: Item, position: Int) -> Boolean)? = null
-    var onTouchListener: ((v: View, event: MotionEvent, adapter: IAdapter<Item>, item: Item, position: Int) -> Boolean)? = null
+    var onPreLongClickListener: LongClickListener<Item>? = null
+    var onLongClickListener: LongClickListener<Item>? = null
+    var onTouchListener: TouchListener<Item>? = null
 
     //the listeners for onCreateViewHolder or onBindViewHolder
     var onCreateViewHolderListener: OnCreateViewHolderListener<Item> = OnCreateViewHolderListenerImpl()
@@ -105,6 +109,7 @@ open class FastAdapter<Item : GenericItem> : RecyclerView.Adapter<RecyclerView.V
     /**
      * the ClickEventHook to hook onto the itemView of a viewholder
      */
+    @Suppress("UNCHECKED_CAST")
     open val viewClickListener: ClickEventHook<Item> = object : ClickEventHook<Item>() {
         override fun onClick(v: View, position: Int, fastAdapter: FastAdapter<Item>, item: Item) {
             if (!item.isEnabled) return
@@ -336,7 +341,7 @@ open class FastAdapter<Item : GenericItem> : RecyclerView.Adapter<RecyclerView.V
      * @return the ViewHolder with the bound data
      */
     override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): RecyclerView.ViewHolder {
-        if (verboseLoggingEnabled) Log.v(TAG, "onCreateViewHolder: $viewType")
+        logger.log("onCreateViewHolder: $viewType")
 
         val typeInstance = getTypeInstance(viewType)
 
@@ -398,7 +403,7 @@ open class FastAdapter<Item : GenericItem> : RecyclerView.Adapter<RecyclerView.V
      * @param holder the viewHolder we unbind the data from
      */
     override fun onViewRecycled(holder: RecyclerView.ViewHolder) {
-        if (verboseLoggingEnabled) Log.v(TAG, "onViewRecycled: " + holder.itemViewType)
+        logger.log("onViewRecycled: " + holder.itemViewType)
         super.onViewRecycled(holder)
         onBindViewHolderListener.unBindViewHolder(holder, holder.adapterPosition)
     }
@@ -409,7 +414,7 @@ open class FastAdapter<Item : GenericItem> : RecyclerView.Adapter<RecyclerView.V
      * @param holder the viewHolder for the view which got detached
      */
     override fun onViewDetachedFromWindow(holder: RecyclerView.ViewHolder) {
-        if (verboseLoggingEnabled) Log.v(TAG, "onViewDetachedFromWindow: " + holder.itemViewType)
+        logger.log("onViewDetachedFromWindow: " + holder.itemViewType)
         super.onViewDetachedFromWindow(holder)
         onBindViewHolderListener.onViewDetachedFromWindow(holder, holder.adapterPosition)
     }
@@ -420,7 +425,7 @@ open class FastAdapter<Item : GenericItem> : RecyclerView.Adapter<RecyclerView.V
      * @param holder the viewHolder for the view which got detached
      */
     override fun onViewAttachedToWindow(holder: RecyclerView.ViewHolder) {
-        if (verboseLoggingEnabled) Log.v(TAG, "onViewAttachedToWindow: " + holder.itemViewType)
+        logger.log("onViewAttachedToWindow: " + holder.itemViewType)
         super.onViewAttachedToWindow(holder)
         onBindViewHolderListener.onViewAttachedToWindow(holder, holder.adapterPosition)
     }
@@ -433,17 +438,17 @@ open class FastAdapter<Item : GenericItem> : RecyclerView.Adapter<RecyclerView.V
      * @return true if we want to recycle anyways (false - it get's destroyed)
      */
     override fun onFailedToRecycleView(holder: RecyclerView.ViewHolder): Boolean {
-        if (verboseLoggingEnabled) Log.v(TAG, "onFailedToRecycleView: " + holder.itemViewType)
+        logger.log("onFailedToRecycleView: " + holder.itemViewType)
         return onBindViewHolderListener.onFailedToRecycleView(holder, holder.adapterPosition) || super.onFailedToRecycleView(holder)
     }
 
     override fun onAttachedToRecyclerView(recyclerView: RecyclerView) {
-        if (verboseLoggingEnabled) Log.v(TAG, "onAttachedToRecyclerView")
+        logger.log("onAttachedToRecyclerView")
         super.onAttachedToRecyclerView(recyclerView)
     }
 
     override fun onDetachedFromRecyclerView(recyclerView: RecyclerView) {
-        if (verboseLoggingEnabled) Log.v(TAG, "onDetachedFromRecyclerView")
+        logger.log("onDetachedFromRecyclerView")
         super.onDetachedFromRecyclerView(recyclerView)
     }
 
@@ -455,7 +460,7 @@ open class FastAdapter<Item : GenericItem> : RecyclerView.Adapter<RecyclerView.V
      */
     open fun getPosition(item: Item): Int {
         if (item.identifier == -1L) {
-            Log.e("FastAdapter", "You have to define an identifier for your item to retrieve the position via this method")
+            Log.e(TAG, "You have to define an identifier for your item to retrieve the position via this method")
             return -1
         }
         return getPosition(item.identifier)
@@ -561,7 +566,7 @@ open class FastAdapter<Item : GenericItem> : RecyclerView.Adapter<RecyclerView.V
         if (position < 0 || position >= globalSize) {
             return null
         }
-        if (verboseLoggingEnabled) Log.v(TAG, "getAdapter")
+        logger.log("getAdapter")
         //now get the adapter which is responsible for the given position
         return adapterSizes.valueAt(floorIndex(adapterSizes, position))
     }
@@ -843,8 +848,8 @@ open class FastAdapter<Item : GenericItem> : RecyclerView.Adapter<RecyclerView.V
      * A ViewHolder provided from the FastAdapter to allow handling the important event's within the ViewHolder
      * instead of the item
      *
-     * @param <Item>
-    </Item> */
+     * @param Item
+     */
     abstract class ViewHolder<Item : GenericItem>(itemView: View) : RecyclerView.ViewHolder(itemView) {
 
         /**
diff --git a/library-core/src/main/java/com/mikepenz/fastadapter/IClickable.kt b/library-core/src/main/java/com/mikepenz/fastadapter/IClickable.kt
index 8412eec81..4af18c499 100644
--- a/library-core/src/main/java/com/mikepenz/fastadapter/IClickable.kt
+++ b/library-core/src/main/java/com/mikepenz/fastadapter/IClickable.kt
@@ -7,6 +7,8 @@ import android.view.View
  */
 typealias ClickListener<Item> = (v: View?, adapter: IAdapter<Item>, item: Item, position: Int) -> Boolean
 
+typealias LongClickListener<Item> = (v: View, adapter: IAdapter<Item>, item: Item, position: Int) -> Boolean
+
 interface IClickable<Item : GenericItem> {
 
     /**
diff --git a/library-core/src/main/java/com/mikepenz/fastadapter/ISelectionListener.kt b/library-core/src/main/java/com/mikepenz/fastadapter/ISelectionListener.kt
index 6312b8484..1f05532b4 100644
--- a/library-core/src/main/java/com/mikepenz/fastadapter/ISelectionListener.kt
+++ b/library-core/src/main/java/com/mikepenz/fastadapter/ISelectionListener.kt
@@ -11,5 +11,5 @@ interface ISelectionListener<Item : GenericItem> {
      * @param item the item who's selection state changed
      * param selected the new selection state of the item
      */
-    fun onSelectionChanged(item: Item?, selected: Boolean)
+    fun onSelectionChanged(item: Item, selected: Boolean)
 }
diff --git a/library-core/src/main/java/com/mikepenz/fastadapter/MutableSubItemList.kt b/library-core/src/main/java/com/mikepenz/fastadapter/MutableSubItemList.kt
index 455ceeaa6..66cd57f9b 100644
--- a/library-core/src/main/java/com/mikepenz/fastadapter/MutableSubItemList.kt
+++ b/library-core/src/main/java/com/mikepenz/fastadapter/MutableSubItemList.kt
@@ -1,10 +1,24 @@
 package com.mikepenz.fastadapter
 
 /**
- * MutableList proxy which will properly set the parent for items added/set.
+ * MutableList proxy which will properly set and remove the parent for items added/set/removed.
  * This is important as otherwise collapsing will not work properly (does not resolve parent relationships)
  */
 class MutableSubItemList<E : ISubItem<*>>(val parent: IParentItem<*>, val list: MutableList<E> = mutableListOf()) : MutableList<E> by list {
+
+    override fun remove(element: E): Boolean {
+        return list.remove(element).also { removed -> if (removed) element.parent = null }
+    }
+
+    override fun removeAt(index: Int): E {
+        return list.removeAt(index).also { element -> element.parent = null }
+    }
+
+    override fun removeAll(elements: Collection<E>): Boolean {
+        elements.filter { list.contains(it) }.forEach { it.parent = null }
+        return list.removeAll(elements)
+    }
+
     override fun add(element: E): Boolean {
         element.parent = parent
         return list.add(element)
@@ -27,6 +41,6 @@ class MutableSubItemList<E : ISubItem<*>>(val parent: IParentItem<*>, val list:
 
     override fun set(index: Int, element: E): E {
         element.parent = parent
-        return list.set(index, element)
+        return list.set(index, element).also { oldElement -> oldElement.parent = null }
     }
 }
\ No newline at end of file
diff --git a/library-core/src/main/java/com/mikepenz/fastadapter/VerboseLogger.kt b/library-core/src/main/java/com/mikepenz/fastadapter/VerboseLogger.kt
new file mode 100644
index 000000000..b8728eed9
--- /dev/null
+++ b/library-core/src/main/java/com/mikepenz/fastadapter/VerboseLogger.kt
@@ -0,0 +1,17 @@
+package com.mikepenz.fastadapter
+
+import android.util.Log
+
+/**
+ * @author pa.gulko zTrap (16.10.2019)
+ */
+internal class VerboseLogger(private val tag: String) {
+
+    var isEnabled = false
+
+    fun log(message: String) {
+        if (isEnabled) {
+            Log.v(tag, message)
+        }
+    }
+}
\ No newline at end of file
diff --git a/library-core/src/main/java/com/mikepenz/fastadapter/items/AbstractItem.kt b/library-core/src/main/java/com/mikepenz/fastadapter/items/AbstractItem.kt
index eb77cb5b2..3477b1a14 100644
--- a/library-core/src/main/java/com/mikepenz/fastadapter/items/AbstractItem.kt
+++ b/library-core/src/main/java/com/mikepenz/fastadapter/items/AbstractItem.kt
@@ -156,9 +156,7 @@ abstract class AbstractItem<VH : RecyclerView.ViewHolder> : IItem<VH> {
      * @param id identifier
      * @return true if identifier equals id, false otherwise
      */
-    override fun equals(id: Int): Boolean {
-        return id.toLong() == identifier
-    }
+    override fun equals(id: Int): Boolean = id.toLong() == identifier
 
     /**
      * If this item equals to the given object
@@ -178,7 +176,5 @@ abstract class AbstractItem<VH : RecyclerView.ViewHolder> : IItem<VH> {
      *
      * @return
      */
-    override fun hashCode(): Int {
-        return java.lang.Long.valueOf(identifier).hashCode()
-    }
+    override fun hashCode(): Int = identifier.hashCode()
 }
diff --git a/library-core/src/main/java/com/mikepenz/fastadapter/listeners/TouchEventHook.kt b/library-core/src/main/java/com/mikepenz/fastadapter/listeners/TouchEventHook.kt
index b41f19571..a0c14ef16 100644
--- a/library-core/src/main/java/com/mikepenz/fastadapter/listeners/TouchEventHook.kt
+++ b/library-core/src/main/java/com/mikepenz/fastadapter/listeners/TouchEventHook.kt
@@ -5,6 +5,9 @@ import android.view.View
 import androidx.recyclerview.widget.RecyclerView
 import com.mikepenz.fastadapter.FastAdapter
 import com.mikepenz.fastadapter.GenericItem
+import com.mikepenz.fastadapter.IAdapter
+
+typealias TouchListener<Item> = (v: View, event: MotionEvent, adapter: IAdapter<Item>, item: Item, position: Int) -> Boolean
 
 abstract class TouchEventHook<Item : GenericItem> : EventHook<Item> {
     abstract fun onTouch(v: View, event: MotionEvent, position: Int, fastAdapter: FastAdapter<Item>, item: Item): Boolean
diff --git a/library-extensions-expandable/src/main/java/com/mikepenz/fastadapter/expandable/ExpandableExtension.kt b/library-extensions-expandable/src/main/java/com/mikepenz/fastadapter/expandable/ExpandableExtension.kt
index 919df356e..0d625ce85 100644
--- a/library-extensions-expandable/src/main/java/com/mikepenz/fastadapter/expandable/ExpandableExtension.kt
+++ b/library-extensions-expandable/src/main/java/com/mikepenz/fastadapter/expandable/ExpandableExtension.kt
@@ -76,7 +76,7 @@ class ExpandableExtension<Item : GenericItem>(private val fastAdapter: FastAdapt
             //this is the entrance parent
             if (allowedParents.size > 0) {
                 // Go on until we hit an item with a parent which was not in our expandable hierarchy
-                val parent = (item as ISubItem<*>).parent
+                val parent = (item as? ISubItem<*>)?.parent
                 if (parent == null || !allowedParents.contains(parent)) {
                     return true
                 }
@@ -271,7 +271,7 @@ class ExpandableExtension<Item : GenericItem>(private val fastAdapter: FastAdapt
      * @return a set with the global positions of all expanded items on the same level as the current item
      */
     fun getExpandedItemsSameLevel(position: Int): List<Int> {
-        fastAdapter.getItem(position).ifExpandableParent { child, parent ->
+        val result = fastAdapter.getItem(position).ifExpandableParent { child, parent ->
             //if it is a SubItem and has a parent, only return the expanded items on the same level
             parent.subItems.asSequence()
                     .filter { it.isExpanded && it !== child }
@@ -279,7 +279,7 @@ class ExpandableExtension<Item : GenericItem>(private val fastAdapter: FastAdapt
                     .map { fastAdapter.getPosition(it) }
                     .toList()
         }
-        return getExpandedItemsRootLevel(position)
+        return result ?: getExpandedItemsRootLevel(position)
     }
 
     /**
@@ -310,13 +310,15 @@ class ExpandableExtension<Item : GenericItem>(private val fastAdapter: FastAdapt
      * toggles the expanded state of the given expandable item at the given position
      *
      * @param position the global position
+     * @param notifyItemChanged true if we need to call notifyItemChanged. DEFAULT: false
      */
-    fun toggleExpandable(position: Int) {
+    @JvmOverloads
+    fun toggleExpandable(position: Int, notifyItemChanged: Boolean = true) {
         val item = fastAdapter.getItem(position) as? IExpandable<*> ?: return
         if (item.isExpanded) {
-            collapse(position)
+            collapse(position, notifyItemChanged)
         } else {
-            expand(position)
+            expand(position, notifyItemChanged)
         }
     }
 
@@ -352,6 +354,24 @@ class ExpandableExtension<Item : GenericItem>(private val fastAdapter: FastAdapt
         }
     }
 
+    /**
+     * collapses (closes) the given collapsible item at the given position with parents who contains this item
+     *
+     * @param position          the global position
+     * @param notifyItemChanged true if we need to call notifyItemChanged. DEFAULT: false
+     */
+    @JvmOverloads
+    fun collapseIncludeParents(position: Int, notifyItemChanged: Boolean = false) {
+        val parents = getExpandableParents(position)
+
+        parents.forEach { collapse(fastAdapter.getPosition(it.identifier)) }
+
+        //we need to notify to get the correct drawable if there is one showing the current state
+        if (notifyItemChanged) {
+            fastAdapter.notifyItemChanged(position)
+        }
+    }
+
     /**
      * expands all expandable items
      *
@@ -398,7 +418,25 @@ class ExpandableExtension<Item : GenericItem>(private val fastAdapter: FastAdapt
     }
 
     /**
-     * calculates the count of expandable items before a given position
+     * opens the expandable item at the given position with parents who contains this item
+     *
+     * @param position          the global position
+     * @param notifyItemChanged true if we need to call notifyItemChanged. DEFAULT: false
+     */
+    @JvmOverloads
+    fun expandIncludeParents(position: Int, notifyItemChanged: Boolean = false) {
+        val parents = getExpandableParents(position)
+
+        parents.forEach { expand(fastAdapter.getPosition(it.identifier)) }
+
+        //we need to notify to get the correct drawable if there is one showing the current state
+        if (notifyItemChanged) {
+            fastAdapter.notifyItemChanged(position)
+        }
+    }
+
+    /**
+     * calculates the count of expanded items before a given position
      *
      * @param from     the global start position you should pass here the count of items of the previous adapters (or 0 if you want to start from the beginning)
      * @param position the global position
@@ -413,6 +451,25 @@ class ExpandableExtension<Item : GenericItem>(private val fastAdapter: FastAdapt
                 .sum()
     }
 
+    /**
+     * Walks through the parents tree while parents are non-null and parents are IExpandable
+     */
+    private fun getExpandableParents(position: Int): List<IExpandable<*>> {
+        val expandable = fastAdapter.getItem(position) as? IExpandable<*> ?: return emptyList()
+
+        // walk through the parents tree
+        val parents = mutableListOf<IExpandable<*>>()
+
+        var element: IExpandable<*>? = expandable
+        while (element != null) {
+            parents.add(element)
+            element = element.parent as? IExpandable<*>
+        }
+
+        // we need to reverse parents for going from root to provided item
+        return parents.reversed()
+    }
+
     companion object {
         private const val BUNDLE_EXPANDED = "bundle_expanded"
 
diff --git a/library-extensions-expandable/src/main/java/com/mikepenz/fastadapter/expandable/items/AbstractExpandableItem.kt b/library-extensions-expandable/src/main/java/com/mikepenz/fastadapter/expandable/items/AbstractExpandableItem.kt
index e1b6292b0..8b6ba05f0 100644
--- a/library-extensions-expandable/src/main/java/com/mikepenz/fastadapter/expandable/items/AbstractExpandableItem.kt
+++ b/library-extensions-expandable/src/main/java/com/mikepenz/fastadapter/expandable/items/AbstractExpandableItem.kt
@@ -22,5 +22,5 @@ abstract class AbstractExpandableItem<VH : RecyclerView.ViewHolder> :
     override val isAutoExpanding: Boolean = true
     override var isSelectable: Boolean
         get() = subItems.isNullOrEmpty()
-        set(value) {}
+        set(_) {}
 }
diff --git a/library-extensions-expandable/src/main/java/com/mikepenz/fastadapter/expandable/items/ModelAbstractExpandableItem.kt b/library-extensions-expandable/src/main/java/com/mikepenz/fastadapter/expandable/items/ModelAbstractExpandableItem.kt
index ece5c0ac9..d0471b7bf 100644
--- a/library-extensions-expandable/src/main/java/com/mikepenz/fastadapter/expandable/items/ModelAbstractExpandableItem.kt
+++ b/library-extensions-expandable/src/main/java/com/mikepenz/fastadapter/expandable/items/ModelAbstractExpandableItem.kt
@@ -27,5 +27,5 @@ abstract class ModelAbstractExpandableItem<Model, Parent, SubItem, VH : Recycler
     override val isAutoExpanding: Boolean = true
     override var isSelectable: Boolean
         get() = _subItems.isNotEmpty()
-        set(value) {}
+        set(_) {}
 }
diff --git a/library-extensions-utils/src/main/java/com/mikepenz/fastadapter/utils/DragDropUtil.kt b/library-extensions-utils/src/main/java/com/mikepenz/fastadapter/utils/DragDropUtil.kt
index 8abf6ea1e..fcda5ef53 100644
--- a/library-extensions-utils/src/main/java/com/mikepenz/fastadapter/utils/DragDropUtil.kt
+++ b/library-extensions-utils/src/main/java/com/mikepenz/fastadapter/utils/DragDropUtil.kt
@@ -1,7 +1,6 @@
 package com.mikepenz.fastadapter.utils
 
 import android.view.MotionEvent
-import androidx.core.view.MotionEventCompat
 import androidx.recyclerview.widget.RecyclerView
 import com.mikepenz.fastadapter.IItemAdapter
 import com.mikepenz.fastadapter.drag.IExtendedDraggable
@@ -20,8 +19,8 @@ object DragDropUtil {
     fun bindDragHandle(holder: RecyclerView.ViewHolder, item: IExtendedDraggable<RecyclerView.ViewHolder>) {
         // if necessary, init the drag handle, which will start the drag when touched
         if (item.touchHelper != null) {
-            item.getDragView(holder)?.setOnTouchListener { v, event ->
-                if (MotionEventCompat.getActionMasked(event) == MotionEvent.ACTION_DOWN) {
+            item.getDragView(holder)?.setOnTouchListener { _, event ->
+                if (event.actionMasked == MotionEvent.ACTION_DOWN) {
                     if (item.isDraggable)
                         item.touchHelper!!.startDrag(holder)
                 }
@@ -30,7 +29,7 @@ object DragDropUtil {
         }
     }
 
-    /*
+    /**
      * This functions handles the default drag and drop move event
      * It takes care to move all items one by one within the passed in positions
      *