Using the junk mail rules is very comfortable to manage junk mails by not rejecting them. With my junk mail folder I'm able to scroll over all mails and have a look for false positives.
After controlling the mails I wanna clear my junk mail folder. To do this in my browser is impossible. STRG + A only selects currently visisble mails and not all in the folder. So I have to STRG + A and delete my junk mail folder for 10-20 times till it's empty.
An option like "Move all to trash" or "Mark all" would be helpfull.