[Regression] kmail hangs when clicking on the systray.

As reported on qt4-preview-feedback mailinglist: http://lists.trolltech.com/pipermail/qt4-preview-feedback/2009-November/001032.html

--------
Issue: When kmail is minimized to the systray, left clicking on it "hangs"
for minutes before kmail appears- if it appears at all that is.
During that "hang time", the systray icon does not respond to
anything at all.

Right click actions are not affected, they work as expected, if the
icon is in a non-hanging state.

First version known w/ regression:
5b4b6b2be7b901ef9a29c37431998034730fa3d3