anchordocking: clean up

git-svn-id: http://svn.freepascal.org/svn/lazarus/trunk@41905 4005530d-fff6-0310-9dd1-cebe43e6787f
IDE: constantified

git-svn-id: http://svn.freepascal.org/svn/lazarus/trunk@41906 4005530d-fff6-0310-9dd1-cebe43e6787f