I have a Vista gadget that has a few DIV's and IMG's. The elements have 'title' attributes set to display a tooltip. If you are in the gadget, and it is focused the tool tips show... like normal. But if you click on the desktop then hover over something that is supposed to have a tooltip nothing shows up until you click the gadget itself and then hover over the item you wish to see a tool tip for.
This is really annoying and I hope someone can shed light on this.
The same is true of all use of the native tool tip classes in Windows applications - they only appear for the active (focussed) window. If you want to work around this the only solution is to roll your own tool tips that appear on mouseenter and disappear on mouseleave.