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Inexplicable black line appearing over my tab?

sparksinthesoftware
sparksinthesoftware
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My firefox updated to the (horrible) new tabs, and now there's an incredibly annoying black line that appears over my Facebook tab that I can't find any way to get rid of. What does this mean? What is it for? How do I kill this stupid thing? With the (terrible) way the new tabs distinguish between the active tab and the inactive tabs (basically just a slightly different, nearly indistinguishable shade of off-white), this black bar is the most striking visual element on my row of tabs, so it grabs the eye the way the active tab should, and it's confusing and distracting.

My firefox updated to the (horrible) new tabs, and now there's an incredibly annoying black line that appears over my Facebook tab that I can't find any way to get rid of. What does this mean? What is it for? How do I kill this stupid thing? With the (terrible) way the new tabs distinguish between the active tab and the inactive tabs (basically just a slightly different, nearly indistinguishable shade of off-white), this black bar is the most striking visual element on my row of tabs, so it grabs the eye the way the active tab should, and it's confusing and distracting.
Attached screenshots

Chosen solution

Do you have the Facebook Container addon?

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All Replies (3)

TyDraniu
TyDraniu
  • Top 25 Contributor
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Chosen Solution

Do you have the Facebook Container addon?

jscher2000 - Support Volunteer
jscher2000 - Support Volunteer
  • Top 25 Contributor
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A number of users have said that the container color line moving from the bottom of the tab to the top of the tab is more distracting. I'm not aware of a built-in way to modify the position, shape, or length of this line, but possibly custom style rules in a userChrome.css file (a community-supported workaround) might help. There's an active subreddit for hacking Firefox's interface with style rules here where you might find more guidance:

https://www.reddit.com/r/FirefoxCSS/

sparksinthesoftware
sparksinthesoftware Question owner
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Thanks guys, that's fixed me, apparently it was the Facebook Container addon that was adding that annoying line.