Description Nick Edgar 2008-04-18 12:38:48 EDT

3.3.2 build

In a tree viewer with elements expanded as in:
+ a
- b
  - c
    + d


toggle a filter which hides 'a', and refresh the viewer.
The expansion state is preserved:
- b
  + c
    + d

Now toggle the filter back on, and refresh again.
The expansion state for c is lost:
+ a
- b
  - c

This is because in AbstractTreeViewer.updateChildren, it reuses the first item for a (previously used by b) and creates a new item for b.  While the expansion state of b is preserved, the expansion state of its children is not.

To solve this efficiently, updateChildren will need to collect expanded elements from subtrees whose items are being reuse and pass this down to the new subtree for the element.

(Jazz work item: 48906)