My siderbar is quite full, so that the last section has no margin to the lower side of the box left. As i used a footline, the space is reduced even more. However, i didn't use short author option in sidebar, so that there is more than enough space above. I tried to include the content of beamerouterthemesidebar.sty to my file, to edit the vertical spaces definded there. But as I'm a Tex newbie, i couldnt handle the resulting errors like "missing begin document" or "beamer@(sth) not defined". My theme is Berkeley. I hope someone could provide a quick fix.
The space between the gray square and white titletext should be used to center the content.