Test the accessiblity tree after a pending modal dialog becomes active.

This was the top dialog and should not be in the tree.

This should be pruned out of the tree.

This button should not be in the tree.

This was the middle dialog and should not be in the tree.

This is the now active dialog. Of course it should be in the tree. This is in the active dialog and should be in the tree.

This is the pending dialog and should not be in the tree.