Open up this fiddle in IE.
When the dialog opens, put any other window partially over the fiddle window, but make sure the dialog box is hidden. You will notice that clicking the fiddle window does nothing unless you move the top window out of the way. Now hide the fiddle window again, but this time leave a little piece of the dialog peeking out from the top window. Clicking the dialog successfully brings the fiddle window to the foreground.
Is there some kind of patch/fix that addresses this annoying IE issue?