Description Evan Hourigan 2008-04-16 18:22:30 EDT

Build ID: M20071023-1652 but using SWT 3.4M5

Steps To Reproduce:
1.  Place a canvas as a primary control in a composite (use grid layout and have it fill vertical), then place a tree as a secondary control in a composite (use gridlayout and make it fill both).
2.  In reaction to either vertical scrollbar events on the tree's vertical scrollbar, or paint events in the tree, use some random means of determining that the canvas needs to become more or less wide than it was previously, and do this, then call layout on the containing composite.  
3.  Make the tree scroll by holding the mouse down on one of the vertical scrolling arrows.  As the code that determines that the canvas needs to become more or less wide while the mouse is being held on the down arrow, the composite will re-lay itself out.  This causes a number of troublesome symptoms:
 a. Scrollbar artifacts/cheese remain painted on the tree's client area.
 b. The scrolling stops since during layout, the arrow's bounds became temporarily not-under the mouse down location (which is what I think is the root of the bug).


More information:
We are using SWT 3.4M5, so the bug definitely exists in that SWT version.