I often help users to troubleshoot issues and one thing that can waste a lot of time and frustration is when a user says that they have tested with hardware acceleration disabled, but in reality they did not restart the browser (so they never tested with it disabled). I recently experienced this - again. This can also lead a user testing on their own down the wrong path as well. We know that the user must restart for the setting to take effect, but we don't communicate that at all. We should remedy this. Options that seem apparent to me: 1) Add simple text on toggle. Something like "Restart Firefox to apply this setting." 2) Same as above but include a link or button that actually restarts Firefox. 3) Force a restart as per bug 1094333 - similar to the e10s switch behavior now. 4) Present an immediate restart now/later dialog. Option #1 could land quickly and easily, but all of these will likely require l10n. Forcing restart immediately (#3) a la e10s, is only on prerelease right now and may make more sense for that feature? Someone may want the toggle to take effect later. It's all a matter of UX of course. We can have a combo of #1/#2 and #4, which would be the most flexible and informative (I think).