One of my player's screens defaults to black background

On the left is his screen, mine is on the right.  All other players see the proper colored background.  Regardless of what I change it to, it shows as black for him.  I have started using grey so that everything is still visible to him, but it's still concerning.  I am not a premium user, and Fog of War is on, but correctly covers the correct thing.  Is there another setting somewhere that would make this an issue for just him? As a note: this is only an issue when I hand draw things in roll20.  When I use a normal battlemap on the map layer, there are no issues.  Only when the standard background is visible.

Apparently there is a firefox add-on called "Dark Reader" which they might be using (looking at the title bar of their browser). It might be that add-on (or a similar one) which is causing their map background to be changed to black instead of the roll20 default colour. I saw this in another thread at <a href="https://app.roll20.net/forum/permalink/9561998/" rel="nofollow">https://app.roll20.net/forum/permalink/9561998/</a>

Thank you.&nbsp; I'll ask them about it.

That appears to be what was causing the issue.&nbsp; Thank you very much! Annoyance averted!