Firefox doesn't allow me to turn off the right mouse context menu. This stems from some widely used javascripts that disable the right context menu, usually to "prevent" image downloading. So, right mouse dragging in Firefox always pops up a context menu unless you disable it in your preferences.
Unfortunately, I tend to use mouse dragging a lot--users need analog input! I'm not being malicious. This setting was engaged in Firefox 3.0 and kind of broke my past two years of applets. I'm mulling about how to (whether to) fix them, and I'll avoid the right mouse button in the future. But, this means you have to either use the standalone or Internet Explorer, Safari, Opera... just about anything but Firefox to get this webpage to function properly.
Don't fret, Apple laptop users don't even get right mouse buttons.