Comment 81 for bug 109943

**Workaround:**

I found that disabling the indeterminate progress progress bar is not enough; the spinning throbber in the tab is also responsible for CPU usage.

I'm using the below in my Thunderbird profile folder's `chrome/userChrome.css` to disable both, resulting in the 15-20% CPU usage disappearing:

    @namespace url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul");

    /* nh2: Progress bar CPU usage fix. */
    /* For some stupid reason we can't match the html:progress that's the first child of this container.
       See https://bugzilla.mozilla.org/show_bug.cgi?id=562977#c61
       So we can't style the progress bar so that it does doesn't get shown only when
       indeterminate (which takes the most CPU), or style it to render faster.
       So for now we hide the entire parent container, thus getting rid of the progress bar entirely.
    */
    #statusbar-progresspanel {
      display: none;
    }

    /* nh2: Tab throbber animations also take a lot of CPU; hide them.
       Unfortunately I didn't find a way to replace them by a static image.
    */
    .tab-throbber[busy] {
      display: none !important;
    }
    .tab-throbber[progress] {
      display: none !important;
    }