applets/taskmanager: avoid updating dragSource when active is false

Merged Fushan Wen requested to merge work/fuf/evildraghandler into master

grabToImage is async, so when an item is grabbed to an image, the drag operation can be already cancelled. When dragSource is not null, MouseHandler will always consider the current drag opertion is to move tasks, which causes the bug.


  1. Drag a file onto a task and hold LMB
  2. Press RMB
  3. Release RMB
  4. Release LMB
  5. Drag a file onto a task again


BUG: 466675 FIXED-IN: 5.27.6

Merge request reports