Small bug report:
UITooltip.SetText resets the widget's world-Z position because it manually assigns a ViewportToWorldPoint to the transform position. This will override the containing panel's depth offset which should be respected so that tooltips can be placed in the proper Z order.
It's an easy fix, though, just record the Z position before the assignment in SetText and then put it back into mPos before it's assigned back to the transform.
