treeview selection can be changed by 'mouseup'

[mm-ryo]

Steps:

1. expand 'Item 1 > Item 2 > Item 3'
2. select 'Item 4'
3. mouse down on outside of treeview control and hold it.
4. drop it on item which does not have children items

actual: the selection has changed expect: the selection shouldn't be changed. if it has changed the selection event should be fired.

Sample: https://stackblitz.com/edit/integralui-treeview-fast-load-pkqegr

[Lidor-Systems]

Its a bug. The mouse up event updates the selection (mostly usable when multiple items are selected), but it shouldn't act when the mouse down is clicked outside of the TreeView.

The fix will be available in next update.

[Lidor-Systems]

The fix is now included in v20.2.