Canceling a drop event is not working

[klimeryk]

Required Information

Version(s) of Ext GWT
Ext GWT 3.0.0b

Browser versions and OS
(and desktop environment, if applicable)

• «Firefox 11, Windows 7»

Virtual Machine
«No»

Description
I wanted to do a custom validation when the dragged files enter a drop area. In order to do so, I've overridden onDragEnter in my custom GridDropTarget:

  @Override
  protected void onDragEnter(DndDragEnterEvent e) {
    super.onDragEnter(e);
    if (!valid) {
      e.setCancelled(true);
      e.getStatusProxy().setStatus(false);
    }
  }

However, this does not cause the drop to be cancelled (and the icon remains the green tick).

Run mode
Development mode

Expected result
The feedback indicator changes to a "not allowed" one and the drop is cancelled (meaning, the dragged elements are not added to the ListStore, etc.)

Actual result
The drop succeeds.

Test case
This custom drop target should reject all drops - but it doesn't.

public class RejectingGridDropTarget<M> extends GridDropTarget<M> {

    public RejectingGridDropTarget(Grid<M> grid) {
        super(grid);
    }
    
    @Override
    public void onDragEnter(DndDragEnterEvent event) {
        super.onDragEnter(event);
        event.setCancelled(true);
        event.getStatusProxy().setStatus(false);
    }
}

Possible fix
The problem seems to lie in DropTarget::handleDragEnter - on line 365, when e.isCancelled (for example, in the custom onDragEnter, as it was in my case), the original event gets its status proxy updated - but the 'cancelled' status of the original event is not updated. The control goes back to DNDManager, where on line 125 the (original) event's cancelled field is checked and will go to the else branch, even though we've tried to cancel the event earlier.

[WesleyMoy]

Thanks for the report. I've filed a bug against the engineering team and will update here as soon as we have a fix.

[vadimmaximov]

I can confirm that this is not working. Can you guys give us a workaround?

[calbertts]

I have the same problem with GXT 3.1

[gui0506]

I have the same problem with GXT 3.1 on February 25, 2015. Please fix it.

[gui0506]

This bug is not fixed. Please make it open again.