This is ONLY on the selected tab. If you play a video on a tab there is no sound.

Leave it playing as you click on a different tab and the sound to the previous tab now plays.

Try to switch back and it fades (as opposed to switches off suddenly.)

The only workaround I've found is to play the tab then switch to another tab and reduce the size AND leave the cursor on the now small, open tab - this then allows me to see the second tab (behind) except the section covered by the small 'top' tab - which is silent of course.

This seems very strange - apparently no issue with sound or drivers, as sound is fine just not on the toppermost tab.

Any ideas gratefully received.