threadPane.css is trying to use its knowledge of tree header anonymous content to set tree header images. Instead, it should set the image on the tree header itself and the global tree header css should be used to ensure that the image is displayed correctly. Note that treecell image headers never show the sort direction so that the same behaviour could cover both scenarios. As a side-effect, this stops the tree header images working in the Classic skin.
Sernding to ben/hyatt who may be working on this issue
Yeah, this is a bug.
Updating QA Contact to email@example.com
This is a Modern2 only issue. Back to hangas.
Sending to Hewitt.
Marking verified on windows (2001-02-15-06-Mtrunk).