migrate to new sidebar, re #4620

git-svn-id: svn://develop.studip.de/studip/trunk@31462 c5b85792-5220-0410-ad23-ed5b6b8ad999
members: prevent losing navigation, fixes #4607

git-svn-id: svn://develop.studip.de/studip/trunk@31463 c5b85792-5220-0410-ad23-ed5b6b8ad999
StEP00249: fix of various size of dialogs, re #4484

git-svn-id: svn://develop.studip.de/studip/trunk@31464 c5b85792-5220-0410-ad23-ed5b6b8ad999