Qt: do not scroll scrollable form if scrollbars aren't visible.


git-svn-id: http://svn.freepascal.org/svn/lazarus/trunk@44503 4005530d-fff6-0310-9dd1-cebe43e6787f
Gtk2: fixed TScrollingWinControl positions update.issue #25909


git-svn-id: http://svn.freepascal.org/svn/lazarus/trunk@44504 4005530d-fff6-0310-9dd1-cebe43e6787f