Your comments

Now 4 years later, is there any hope for this feature? I understand if you're busy, I am too :)

Btw Sidewise has been probably the most important extension for me for several years (yes, I have donated). And btwbtw your picture brings good memories!

I figured that if I make the video full screen or take it out of full screen, if it already is so, it starts playing again. It's a work around, but it's still annoying.
I should also add that it sometimes shows a blank, black screen while still playing the sound of the video, instead of not playing the video at all.