Replaces the default activity indicator (throbber) with a spinning rotor from a Wankel engine. On Firefox versions up to 3.6, a spinning rotor is also placed on the individual tabs. For Firefox 3.7, the loading pie chart is replaced with a pie chart styled rotor image.
This does not replace your current theme, and should work with most themes.
On later versions of Firefox, 3.5 and up, the activity indicator is not shown on the top toolbar. This can be fixed by right clicking on the toolbar, and selecting customize. Once you are in the Customize Toolbar window, just drag the activity indicator to where ever you want it.