Improvements to behavior for gizmo tool-tips.
- 2D gizmos no longer cancel tool-tips on cursor motion
(matching the behavior of UI widgets).
- 3D gizmos still close on motion since 3D gizmos may have a large
on-screen area which would cause them to stay visible even after the
cursor has been moved a large distance. The motion threshold is used
so they don't close on unintended cursor motion.
- Changing highlighted gizmo now cancels the tool-tip & resets the timer.
6868202899