- Add onDragOver/onDrop preventDefault on container div (React level) to always block browser default file-open behavior - Add DOM fallback in useCanvasSetup if ref is somehow null - setupDragDrop's native listeners handle the actual upload logic
- Add onDragOver/onDrop preventDefault on container div (React level) to always block browser default file-open behavior - Add DOM fallback in useCanvasSetup if ref is somehow null - setupDragDrop's native listeners handle the actual upload logic