Comment 86 for bug 109943

Yes, `list-style-image: none !important;` also fixes it.

> Strange that both together use the same CPU like when only one is active.

I don't find that strange: Using either progress bar or animated PNG throbber, the screen now has to be drawn at many frames per second. Once you have to redraw, redrawing a bit more doesn't make a big difference.

Separetely: Also useful to know for posterity, the upgrade from Thunderbird 60 to 68 made the indeterminate progress bar a lot more jumpy (it looks like around 10 FPS while the original was much smoother) - but to my surprise that increased jumpiness still didn't reduce CPU usage a lot.