The tab bar has several weird issues...

[TheEvilKingBowser]

• Lower corners of the current selected tab have random black pixels in them
  
• Tabs have gaps between their left edge and the right edge of the tab adjacent to them, both when selected and when highlighted.
  
• However, some tabs have the opposite problem, making the border between the tabs appear to be 2 pixels wide instead of 1:
  
• The "new tab" button looks like it's been vertically stretched by 1 pixel
  
  Please please please fix these, they're positively driving me mad. I'm using Firefox 89.0, by the way.

[black7375]

Are you using compact mode?
Then it's a bug I know, and I'm taking the time to fix it within the weekend.

[TheEvilKingBowser]

Huh... weird. I'm actually using normal mode. Are there any about:config options I may have changed in the past and forgotten about, that might be causing these issues to happen even in normal mode?

[black7375]

It is possible. It has been relatively untested since it was initially intended to be put into a tip.

[TheEvilKingBowser]

Well, hopefully the next update will fix it in normal mode as well as compact. Thanks for your help! :D

[black7375]

@TheEvilKingBowser Could you try again?

[TheEvilKingBowser]

It's actually been made even worse... the spacing issues seem to mostly be gone, but the black spots have only grown larger.

[TheEvilKingBowser]

Oh, and nevermind about the spacing issues being gone. They're still there, you just need to open a bunch of tabs to see them.

[black7375]

but the black spots have only grown larger.

This is a previously reported issue. #12
Please enable the following setting: svg.context-properties.content.enabled.

[black7375]

It seems to have been fixed in the latest version.