Pressing ESC while on a drag operation makes drag visual to be disappeared and OnDragCancelled not to be called.

DragDropOperation is removed when pressing esc button. but this is skipping OnDragCancelled so it can disrupt user's UMG drag operation logic. 

1) Create a new widget blueprint(A, B)

2) Create drag setup(Detect drag at OnMousePreview, CreateDragandDropOperation at OnDragDetected) in B

3) Place B on A

4) Make persistent level blueprint to create and add the A widget into viewport

5) Run in PIE

6) Press esc while dragging the widget

Here is sample project [Link Removed]