User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:33.0) Gecko/20100101 Firefox/33.0 Build ID: 20141107170804 Steps to reproduce: Close all other tabs and play HTML5 audio (for example from http://serialpodcast.org). Confirm that the screensaver has been disabled by typing this command into a DOS prompt: powercfg -requests The command will show that Firefox has disabled the screensaver: DISPLAY: [PROCESS] \Device\HarddiskVolume3\[snip]\firefox.exe Now pause the HTML5 audio. Wait 10 seconds or so to give system time to update status. Type the aforementioned command again into DOS prompt. Firefox will still be disabling the screensaver: DISPLAY: [PROCESS] \Device\HarddiskVolume3\[snip]\firefox.exe You can confirm the cause by refreshing the page with audio on it (so that it is no longer playing) or closing the tab, waiting 10 seconds, then running the same DOS command again, and you will see that the screensaver will no longer be disabled. DISPLAY: None. Actual results: Screensaver was disabled while playing audio (correct behaviour). Screensaver was disabled while audio was paused (incorrect behaviour). Expected results: The screensaver should not be disabled if the audio is paused.
I went into Power Options and switched the setting "Turn off the display" to 1 minute, saved changes, and then switched it back to the original setting. This has somehow fixed the bug described above. I'm not sure whether this is a Windows bug or a Firefox bug, but I'd like to monitor it for a few days to see if the bug returns.
Any further information?