IDE: update DisplayState when switching tabs via mouse

git-svn-id: http://svn.freepascal.org/svn/lazarus/trunk@39781 4005530d-fff6-0310-9dd1-cebe43e6787f
LCL: TMenuItem.AddHandler: changed AsLast to AsFirst for consistency and implemented it

git-svn-id: http://svn.freepascal.org/svn/lazarus/trunk@39782 4005530d-fff6-0310-9dd1-cebe43e6787f
LCL: TMenuItem.AddHandler: changed AsLast to AsFirst for consistency and implemented it

git-svn-id: http://svn.freepascal.org/svn/lazarus/trunk@39783 4005530d-fff6-0310-9dd1-cebe43e6787f