after moving tasks, unselect before restoring selection
bug :
- create empty project, add 3 tasks
- select second task (middle), click move upward button -> 'middle' task is moved first accordingly but third task is now selected as well. Moving a single task upward multiple times is slow (you need to unselect every time)
fix : after moving, before restoring selection on new tree, unselect every task (= don't keep old selection) I've mirrored the fix on move down function too even if the selection bug is not apparent in this direction (node selection doesn't change).