The right way to make a tree widget that consumes the width and height of a window is to place it inside a vertical box (with a flex of 100%). This doesn't work and neither does placing basic tables inside boxes. An assertion is thrown during the reflow of the table.
Tables and trees now work in boxes. However tables have some bugs that prevent them from properly being contrained. Hyatt was looking at these issue.
This bug is being closed. Boxes are behaving properly. Tables are behaving properly. There's just no way to do this without enhancements/changes.
BULK MOVE: Changing component from XUL to XP Toolkit/Widgets: XUL. XUL component will be deleted.