On Linux, Mac and Windows with a debug Mozilla build from this morning around 8 am, I am not able to activate a sidebar tab by clicking into it's title bar. Sofar I hanen't figure out how I can switch to another sidebar tab!
forget to say that I am using the trunk.
*** This bug has been marked as a duplicate of 59613 ***
verified dup of 59613 "[modern theme] Can't switch tabs in sidebar"