Macosx 10.5.7, Tux Paint 0.9.20:
My young son is managing to get tux paint into a state where the blue highlighting on the 'tool' button on the left doesn't correspond to the button that he's selected. The highlighting instead seems to be on the previous tool he was using, and another click on the appropriate tool button restores the state to normal. Using the tool doesn't change how the highlighting looks in the tool bar. He seems to reproduce it maybe 1/5 of the time he switches tools, while I can't reproduce it by myself at all.
The little guy is aged 2 1/2, not terribly verbal, and he's using a USB "mini" mouse (with clickable scroll wheel) that we got at a trade show, since a full sized one is awkward in his hands, and the touch pad on the laptop even more so. I suspect the bug is somehow involved in mashing the mouse buttons or dragging while clicking, and I'm fairly sure the keyboard is uninvolved.
This isn't actually bothersome to us, so feel free to mark it as low priority, or unfixable, given the information I'm providing.
I'm comfortable with unix development tools, but have no relevant gui or mac experience - given that, I'm happy to help out in any way I can.