Microsoft's Developer Toolbar
If you use Microsoft's Developer Toolbar, you know that its pretty cool and a great source to get a Website DOM. You can use the tool to debug information, or to figure out why objects aren't being displayed correctly.
One problem that I have with the toolbar is the Ruler. For some reason every once in a while when I type in Shift-R I see the ruler tool. This is very annoying. However, this is a bug within IE and not the Developer Toolbar. For some reason the Ctrl key is still recognized as being pressed.
The quick fix is to press both Ctrl buttons. This resets the keyboard and you'll be able to type in a capitol R with no problem.