Major annoyance . . . solved!

This is handy, and I discovered it by accident.

I don't know how many times I've wished you could cycle through the tabs in a Mozilla window in the same way as you can through open windows using Alt-Tab. Turns out you can. Cycle left-to right by typing Ctrl-PgDn, or right-to-left with Ctrl-PgUp.

Unlike several other handy Mozilla functions, there isn't a menu option for this. After all, why would you waste time clicking through menu options when you can just click on the tab? So the user interface doesn't document this much-appreciated hotkey. It does, however, appear in the Mozilla FAQ.