Merge pull request #299 from enisn/2.4-textfield-validation-fix

Don't ignore empty string for validation

src/UraniumUI.Material/Controls/TextField.cs

@@ -89,7 +89,7 @@ private void EntryView_TextChanged(object sender, TextChangedEventArgs e)
             UpdateState();
         }
 
-        if (!string.IsNullOrEmpty(e.NewTextValue))
+        if (e.NewTextValue != null)
         {
             CheckAndShowValidations();
         }