fix: Minimap: Ensure scrolling and drawing are in sync
http://bugs.activestate.com/show_bug.cgi?id=100091

(integrated from komodo (trunk) change 81514 by toddw)

git-svn-id: http://svn.openkomodo.com/repos/openkomodo/trunk@13485 b87d16e7-d29f-4ee1-b5ec-817d645d335f