diff --git a/packages/dockview-core/src/dnd/abstractDragHandler.ts b/packages/dockview-core/src/dnd/abstractDragHandler.ts
index 0e452dcf3..b2f6d0475 100644
--- a/packages/dockview-core/src/dnd/abstractDragHandler.ts
+++ b/packages/dockview-core/src/dnd/abstractDragHandler.ts
@@ -25,7 +25,7 @@ export abstract class DragHandler extends CompositeDisposable {
         this.configure();
     }
 
-    abstract getData(dataTransfer?: DataTransfer | null): IDisposable;
+    abstract getData(event: DragEvent): IDisposable;
 
     protected isCancelled(_event: DragEvent): boolean {
         return false;
@@ -60,7 +60,7 @@ export abstract class DragHandler extends CompositeDisposable {
                 this.el.classList.add('dv-dragged');
                 setTimeout(() => this.el.classList.remove('dv-dragged'), 0);
 
-                this.dataDisposable.value = this.getData(event.dataTransfer);
+                this.dataDisposable.value = this.getData(event);
 
                 if (event.dataTransfer) {
                     event.dataTransfer.effectAllowed = 'move';
diff --git a/packages/dockview-core/src/dnd/groupDragHandler.ts b/packages/dockview-core/src/dnd/groupDragHandler.ts
index 0a6f55008..9cc5d58a9 100644
--- a/packages/dockview-core/src/dnd/groupDragHandler.ts
+++ b/packages/dockview-core/src/dnd/groupDragHandler.ts
@@ -43,7 +43,9 @@ export class GroupDragHandler extends DragHandler {
         return false;
     }
 
-    getData(dataTransfer: DataTransfer | null): IDisposable {
+    getData(dragEvent: DragEvent): IDisposable {
+        const dataTransfer = dragEvent.dataTransfer;
+
         this.panelTransfer.setData(
             [new PanelTransfer(this.accessorId, this.group.id, null)],
             PanelTransfer.prototype