treeview: Don't claim event sequence too early
We want to claim the event sequence in the click gesture when appropriate, such as activating a row or clicking an editable cell, but this is currently done too early, preventing other gestures for drag-and-drop and rubberband selection entirely.
Fixes #3649 (closed) (once !4882 (merged) is merged)
Fixes #3985 (closed)
Fixes #4206 (closed)
Fixes #4669 (closed)
Edited by Mat