Last modified: 2014-11-20 20:18:23 UTC
In MW we have a hack that moves the dialog overlay to zIndex 101 (from 1), but the hack to move the toolbar to zIndex 100 is in core, so in core the toolbar is always on top of the global overlay.
Change 174688 had a related patch set uploaded by Esanders: Fix z-indexes in core https://gerrit.wikimedia.org/r/174688