fix: ignore drag & drop from unrelated events #1968 (#2346)

If an event is not from the current blocknote editor, or coming from another blocknote editor on the page, we should not be capturing that event.

Author: nperez0111

packages/core/src/extensions/SideMenu/SideMenu.ts

@@ -380,6 +380,20 @@ export class SideMenuView<
       return;
     }
 
+    // Relevance gate: Only handle drags that belong to BlockNote
+    // This prevents interference with external drag-and-drop libraries
+    // by avoiding calls to closeDropCursor() for non-BlockNote drags
+    const isBlockNoteDrag =
+      this.pmView.dragging !== null ||
+      this.isDragOrigin ||
+      event.dataTransfer?.types.includes("blocknote/html") ||
+      (event.target instanceof Node && this.pmView.dom.contains(event.target));
+
+    if (!isBlockNoteDrag) {
+      // Not a BlockNote-related drag, return early without any processing
+      return;
+    }
+
     const dragEventContext = this.getDragEventContext(event);
 
     if (!dragEventContext || !dragEventContext.isDropPoint) {
@@ -419,6 +433,23 @@ export class SideMenuView<
    *  - Whether the drop event is within the bounds of the current editor instance
    */
   getDragEventContext = (event: DragEvent) => {
+    // Relevance gate: Only handle drags that belong to BlockNote
+    // Check if at least one of the following is true:
+    // 1. ProseMirror drag started in an editor
+    // 2. Side menu drag
+    // 3. BlockNote-specific data type in the drag
+    // 4. (optional stricter mode) Event target is inside this editor
+    const isBlockNoteDrag =
+      this.pmView.dragging !== null ||
+      this.isDragOrigin ||
+      event.dataTransfer?.types.includes("blocknote/html") ||
+      (event.target instanceof Node && this.pmView.dom.contains(event.target));
+
+    if (!isBlockNoteDrag) {
+      // Not a BlockNote-related drag, return early
+      return undefined;
+    }
+
     // We need to check if there is text content that is being dragged (select some text & just drag it)
     const textContentIsBeingDragged =
       !event.dataTransfer?.types.includes("blocknote/html") &&
@@ -477,6 +508,19 @@ export class SideMenuView<
       return;
     }
 
+    // Relevance gate: Only handle drags that belong to BlockNote
+    // This prevents interference with external drag-and-drop libraries
+    const isBlockNoteDrag =
+      this.pmView.dragging !== null ||
+      this.isDragOrigin ||
+      event.dataTransfer?.types.includes("blocknote/html") ||
+      (event.target instanceof Node && this.pmView.dom.contains(event.target));
+
+    if (!isBlockNoteDrag) {
+      // Not a BlockNote-related drag, return early without any processing
+      return;
+    }
+
     const context = this.getDragEventContext(event);
     if (!context) {
       this.closeDropCursor();