Feature request: tooltip auto-close when owner no longer visible

[CrawfordW]

Occasionally I get an orphan tooltip that can't be closed. For example, if I move over a button in a drawer briefly before closing the drawer, the button tooltip may remain visible. The only way to get rid of it is to open the drawer again and hover over the button.
I've had to add extra code to handle this, but it's a pain to do it for every one of hundreds of widgets that have tips.