openglcontrol: qt: invalidate works, patch 27066

git-svn-id: http://svn.freepascal.org/svn/lazarus/trunk@46940 4005530d-fff6-0310-9dd1-cebe43e6787f
examples: openglcontrol: clean up

git-svn-id: http://svn.freepascal.org/svn/lazarus/trunk@46941 4005530d-fff6-0310-9dd1-cebe43e6787f