skins: mac: another tweak to catch oversized retina icons
* this is for the editor tabstrip drop down menu

(integrated from komodo (trunk) change 81829 by toddw)

git-svn-id: http://svn.openkomodo.com/repos/openkomodo/trunk@13592 b87d16e7-d29f-4ee1-b5ec-817d645d335f