diff --git a/src/main/webapp/app/lecture/pdf-preview/pdf-preview-enlarged-canvas/pdf-preview-enlarged-canvas.component.ts b/src/main/webapp/app/lecture/pdf-preview/pdf-preview-enlarged-canvas/pdf-preview-enlarged-canvas.component.ts
index 36e955f1a97f..725c45ab4094 100644
--- a/src/main/webapp/app/lecture/pdf-preview/pdf-preview-enlarged-canvas/pdf-preview-enlarged-canvas.component.ts
+++ b/src/main/webapp/app/lecture/pdf-preview/pdf-preview-enlarged-canvas/pdf-preview-enlarged-canvas.component.ts
@@ -14,20 +14,23 @@ type NavigationDirection = 'next' | 'prev';
 export class PdfPreviewEnlargedCanvasComponent {
     enlargedCanvas = viewChild.required<ElementRef<HTMLCanvasElement>>('enlargedCanvas');
 
-    readonly DEFAULT_SLIDE_HEIGHT = 800;
+    readonly DEFAULT_ENLARGED_SLIDE_HEIGHT = 800;
 
+    // Inputs
     pdfContainer = input.required<HTMLDivElement>();
     originalCanvas = input<HTMLCanvasElement>();
     totalPages = input<number>(0);
 
-    isEnlargedViewOutput = output<boolean>();
-
+    // Signals
     currentPage = signal<number>(1);
 
+    //Outputs
+    isEnlargedViewOutput = output<boolean>();
+
     constructor() {
         effect(
             () => {
-                this.displayEnlargedCanvas(this.originalCanvas()!, false);
+                this.displayEnlargedCanvas(this.originalCanvas()!);
             },
             { allowSignalWrites: true },
         );
@@ -65,8 +68,7 @@ export class PdfPreviewEnlargedCanvasComponent {
         }
     };
 
-    displayEnlargedCanvas(originalCanvas: HTMLCanvasElement, isVertical: boolean) {
-        this.adjustPdfContainerSize(isVertical);
+    displayEnlargedCanvas(originalCanvas: HTMLCanvasElement) {
         this.currentPage.set(Number(originalCanvas.id));
         this.toggleBodyScroll(true);
         setTimeout(() => {
@@ -109,7 +111,7 @@ export class PdfPreviewEnlargedCanvasComponent {
 
         if (originalCanvas.height > originalCanvas.width) {
             // Vertical slide
-            const fixedHeight = this.DEFAULT_SLIDE_HEIGHT;
+            const fixedHeight = this.DEFAULT_ENLARGED_SLIDE_HEIGHT;
             scaleY = fixedHeight / originalCanvas.height;
             scaleX = containerWidth / originalCanvas.width;
         } else {
@@ -174,7 +176,7 @@ export class PdfPreviewEnlargedCanvasComponent {
     adjustPdfContainerSize(isVertical: boolean): void {
         const pdfContainer = this.pdfContainer();
         if (isVertical) {
-            pdfContainer.style.height = `${this.DEFAULT_SLIDE_HEIGHT}px`;
+            pdfContainer.style.height = `${this.DEFAULT_ENLARGED_SLIDE_HEIGHT}px`;
         } else {
             pdfContainer.style.height = '60vh';
         }
diff --git a/src/main/webapp/app/lecture/pdf-preview/pdf-preview-thumbnail-grid/pdf-preview-thumbnail-grid.component.html b/src/main/webapp/app/lecture/pdf-preview/pdf-preview-thumbnail-grid/pdf-preview-thumbnail-grid.component.html
index f3293aa1cf83..24b713acb796 100644
--- a/src/main/webapp/app/lecture/pdf-preview/pdf-preview-thumbnail-grid/pdf-preview-thumbnail-grid.component.html
+++ b/src/main/webapp/app/lecture/pdf-preview/pdf-preview-thumbnail-grid/pdf-preview-thumbnail-grid.component.html
@@ -1,6 +1,7 @@
 <div class="pdf-container" #pdfContainer>
     @if (isEnlargedView()) {
         <jhi-pdf-preview-enlarged-canvas-component
+            [style]="{ display: 'contents' }"
             [pdfContainer]="pdfContainer"
             [totalPages]="totalPages()"
             [originalCanvas]="originalCanvas()"
diff --git a/src/main/webapp/app/lecture/pdf-preview/pdf-preview-thumbnail-grid/pdf-preview-thumbnail-grid.component.ts b/src/main/webapp/app/lecture/pdf-preview/pdf-preview-thumbnail-grid/pdf-preview-thumbnail-grid.component.ts
index e6387065efaf..84a220ad8cba 100644
--- a/src/main/webapp/app/lecture/pdf-preview/pdf-preview-thumbnail-grid/pdf-preview-thumbnail-grid.component.ts
+++ b/src/main/webapp/app/lecture/pdf-preview/pdf-preview-thumbnail-grid/pdf-preview-thumbnail-grid.component.ts
@@ -17,27 +17,29 @@ export class PdfPreviewThumbnailGridComponent {
     pdfContainer = viewChild.required<ElementRef<HTMLDivElement>>('pdfContainer');
 
     readonly DEFAULT_SLIDE_WIDTH = 250;
-    readonly DEFAULT_SLIDE_HEIGHT = 800;
 
+    // Inputs
     currentPdfUrl = input<string>();
     appendFile = input<boolean>();
 
-    isPdfLoading = output<boolean>();
-
+    // Signals
     isEnlargedView = signal<boolean>(false);
     totalPages = signal<number>(0);
     selectedPages = signal<Set<number>>(new Set());
     originalCanvas = signal<HTMLCanvasElement | undefined>(undefined);
 
+    // Outputs
+    isPdfLoading = output<boolean>();
     totalPagesOutput = output<number>();
     selectedPagesOutput = output<Set<number>>();
 
+    // Injected services
     private readonly alertService = inject(AlertService);
 
     constructor() {
         effect(
             () => {
-                this.loadOrAppendPdf(this.currentPdfUrl()!, false);
+                this.loadOrAppendPdf(this.currentPdfUrl()!, this.appendFile());
             },
             { allowSignalWrites: true },
         );
@@ -186,7 +188,6 @@ export class PdfPreviewThumbnailGridComponent {
      * @param originalCanvas - The original canvas element of the PDF page to be enlarged.
      * */
     displayEnlargedCanvas(originalCanvas: HTMLCanvasElement) {
-        //const isVertical = originalCanvas.height > originalCanvas.width;
         this.originalCanvas.set(originalCanvas);
         this.isEnlargedView.set(true);
     }
diff --git a/src/main/webapp/app/lecture/pdf-preview/pdf-preview.component.ts b/src/main/webapp/app/lecture/pdf-preview/pdf-preview.component.ts
index 74ed6f618b1c..c61848cc5768 100644
--- a/src/main/webapp/app/lecture/pdf-preview/pdf-preview.component.ts
+++ b/src/main/webapp/app/lecture/pdf-preview/pdf-preview.component.ts
@@ -32,6 +32,7 @@ export class PdfPreviewComponent implements OnInit, OnDestroy {
     attachmentSub: Subscription;
     attachmentUnitSub: Subscription;
 
+    // Signals
     course = signal<Course | undefined>(undefined);
     attachment = signal<Attachment | undefined>(undefined);
     attachmentUnit = signal<AttachmentUnit | undefined>(undefined);
@@ -202,6 +203,8 @@ export class PdfPreviewComponent implements OnInit, OnDestroy {
 
             const objectUrl = URL.createObjectURL(this.currentPdfBlob()!);
             this.currentPdfUrl.set(objectUrl);
+            this.appendFile.set(false);
+            this.dialogErrorSource.next('');
         } catch (error) {
             this.alertService.error('artemisApp.attachment.pdfPreview.pageDeleteError', { error: error.message });
         } finally {
@@ -233,13 +236,12 @@ export class PdfPreviewComponent implements OnInit, OnDestroy {
             this.selectedPages()!.clear();
 
             const objectUrl = URL.createObjectURL(this.currentPdfBlob()!);
-            this.appendFile.set(true);
             this.currentPdfUrl.set(objectUrl);
+            this.appendFile.set(true);
         } catch (error) {
             this.alertService.error('artemisApp.attachment.pdfPreview.mergeFailedError', { error: error.message });
         } finally {
             this.isPdfLoading.set(false);
-            this.appendFile.set(false);
             this.fileInput()!.nativeElement.value = '';
         }
     }