I KNOW! When you hit Alt+F1, the switchbar collapses. The treebar always shows the same icons as the switchbar, so the icon changes.
If you're trying to say the server branch you have selected should be collapsed, I agree, but I wouldn't call it a bug. It's been mentioned a few times that the treebar isn't supposed to be identical to the switchbar.
That is correct, ALT+F1 is a Switchbar feature, not a Treebar feature. It is designed to expand/collapse the Status button in the switchbar. This feature cannot be used for the Treebar which works differently to the Switchbar.