Which versions of Office have the behavior where the Quick Access Toolbar tooltip displays below the ribbon like that?
I checked Office 2010 and Office 2013 and neither behave the way you suggest. It immediately felt like a bug when I saw it, to be honest.
Also the work around you provide doesn't seem to work, or at least I can't get it to work, when also wanting to keep the multi-line tooltip like Dodd had pictured. It only seems to support single line tool tips.
I am just writing this reply to help others in future. I found an easy fix for the placement behavior by writing this code:
private void SetScreenTipPlacement(FrameworkElement element)
const double X_Y_OFFSET = 10.0;