fix: Editor: Mac: Fixup drawing glitch in the editor
http://bugs.activestate.com/show_bug.cgi?id=99863
* moves the invalidate call to where the scroll occurs, to avoid drawing lockups
rn=

(integrated from komodo (trunk) change 81719 by toddw)

git-svn-id: http://svn.openkomodo.com/repos/openkomodo/trunk@13567 b87d16e7-d29f-4ee1-b5ec-817d645d335f