Tooltips show up as windows in WinXP TaskBar
I first noticed this in Mustang b72, but I couldn't swear it wasn't there earlier. When I have a JFileChooser open and I hover the mouse pointer over the "Open" or "Cancel" button, a tooltip appears and, at the same time, a new button appears in the TaskBar as if I had opened another window. The button contains the new coffee-cup logo but no title, and it disappears when the tooltip does. I've tried this in the SwingSet demo, and it happens under Metal, Motif and Windows L&F's. Under Metal L&F, it also happens with the "Create New Folder" and "Details" buttons up top, but under Windows L&F it doesn't.
Is this a known bug? Is anyone else seing it?
I don't know if it matters, but I see the same kind of untitled button in the TaskBar when my splash screen (an AWT Window) is visible.