Created attachment 41425 [details]
The GarageBand Lesson Store has aqua scroll bars in addition to the internal black vertical scroll bar.
Steps to Reproduce:
1. Open GarageBand
2. If the Lesson Store is selected in the GarageBand window’s sidebar, select a different item, quit GarageBand, and repeat from step 1.
3. In the GarageBand window, select Lesson Store on the left.
The Lesson Store has both aqua scroll bars and an internal black vertical scroll bar. See screenshot.
This was caused by <http://trac.webkit.org/changeset/48064>, the fix for bug 28614 (which interestingly didn’t include a regression test).
r48064 (bug 28614) was an aggressive version of a fix. Bug 29167 modifies it to be more conservative. I wonder if that patch would help this bug too.
Created attachment 42576 [details]
Made FrameView track whether it’s allowed to have scrollbars again
Bug 29167 attachment 42627 [details] should fix this.
*** This bug has been marked as a duplicate of bug 29167 ***