User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:42.0) Gecko/20100101 Firefox/42.0 Build ID: 20151029151421 Steps to reproduce: Play any sound in a tab (only with HTML5 player, e.g. on Youtube, it seems Flash is not affected), mute the tab (mute icon appears in tab) and change the audio output device in Windows. Actual results: The audio of the muted can be heard again with the new device but the mute icon is still visible. If tab is reloaded or another video is started (e.g. on Facebook), the mute state is applied correctly. Expected results: The tab should still be muted after the device switch.