Highlighted tool button isn't the active tool

You can see this by doing the following:

1. Click the 2-Point Line tool button - The button becomes highlighted and the 2-Point Line tool becomes active.
2. Click the Horizontal Line tool button - The button becomes highlighted and the Horizontal Line tool becomes active. The 2-Point Line tool button REMAINS HIGHLIGHTED.
3. Click the 2-Point Line tool button - The button becomes UNHIGHLIGHTED, the 2-Point Line tool becomes active and the Horizontal Line tool button remains HIGHLIGHTED.

So now you're using the 2-point line tool even though it appears to be deselected and the horizontal line tool appears to be activated.

I can also click on all the buttons and they all highlight as though they're all active at once and then click on any one of them again and it becomes unhighlighted while all the others remain highlighted but it is actually the only one that's active. Crazy!

If this is a bug I can file it but I first want to make sure it's not a configuration mistake or I'm just using the program the wrong way.