ID 216841 - The scroll bar position will be reset to default if you move the mouse away while scrolling

Problem Summary

If you try and scroll using the mouse on a menu scroll bar, then move the mouse slightly outside the scroll bar area while you still have the mouse button pressed, the scroll bar gets reset and jumps back to the start.

Reproduction Steps

1. open Katana and the Crowd Example Project
2. expand all in the Scene Graph
3. try scrolling down while having the LMB pressed, then move the mouse slightly to the left or right outside the scroll bar area.

Result: you will see the scroll bar jumps back to the start and you lose your current scroll position.

Reproduced by support

Reproduced in 1.6v3 up to 2.5v1 beta.

Expected Behaviour

The scroll bar should maintain the correct position during the entire scroll operation, whether the mouse is moved away from the scroll bar focus or not.

Actual Behaviour

Moving the mouse outside the scroll bar focus area will reset the scroll bar position to default/start.