Search Support

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More

How to restore tabs of Developer Tools' Inspector pane after they mysteriously disappear?

  • 4 replies
  • 1 has this problem
  • Last reply by WIDEnet

more options

I initially thought this was a UX issue, but it appears it may be a straight up bug; I wanted to ask here first before I report and assess if others are observing it. Regardless, its a pretty horrible problem either way making web development with Firefox an incredibly frustrating experience, to say the least.

Essentially, the problem is this: sometimes, seemingly at random, when I click a tab in the Developer Tools "Inspector" pane (Rules, Layout, etc) the entire inspector pane (aside from the DOM) will just vanish. I have repro'd it with the dark theme and with the pane docked to the right, but its been difficult to get it to repro in other conditions (clean profile, light theme, etc) since there is no obvious consistency in whether it occurs or not; sometimes it won't happen at all for a while, and sometimes it happens every other time I click a tab.

When it does happen, I've tried everything I can think of but I can find no way to restore the tabs, even by reloading the page, closing the developer tools, switching between panes, switching between DOM elements, trying every option I can think of, etc. except by closing the entire browser tab and opening another. Its infuriating. to say the least, and significant hit to my productivity in Firefox. Any ideas?

The "upload images" feature of this page appears broken, as it gets endlessly stuck on "Uploading..." (not to mention primitive—you can't just copy and paste them directly into post like any modern site), and there isn't any obvious support for Markdown (maybe there is, but it isn't exposed anywhere), so I'll just do things the archaic way and post links to screenshots of the problem on imgur:

Before: https://imgur.com/a/i7NlZ2g

After: https://imgur.com/a/XH2XYLh

All Replies (4)

more options

Quick update: It just occured again, this time in the split inspector view with the rules pane on the left and the other ones as tabs on the right. Screenshot: https://imgur.com/a/VBbT16L

Also, oddly, I get formatting tools (in some weird non-Markdown language) in this comment reply, but not in my original post? What?

more options

If you use extensions ("3-bar" menu button or Tools -> Add-ons -> Extensions) that can block (wanted) content (Adblock Plus, NoScript, Disconnect, Ghostery, Privacy Badger, uBlock Origin) always make sure such extensions do not block (wanted) content.

Start Firefox in Safe Mode to check if one of the extensions ("3-bar" menu button or Tools -> Add-ons -> Extensions) or if hardware acceleration is is causing the problem.

  • switch to the DEFAULT theme: "3-bar" menu button or Tools -> Add-ons -> Appearance
  • do NOT click the "Refresh Firefox" button on the Safe Mode start window
more options

It's not Markdown, it's wikitext from back in the day.

Are you docking on the right/left, or floating the tools in a separate window?

My only thought about restoring the display when it happens would be to change the docking to the bottom and then back to your preferred position. No idea whether that would help.

There's a board for discussing DevTools over here (not part of Support), and they might have seen this or need to know about it:

https://discourse.mozilla.org/c/devtools

more options

cor-el said

If you use extensions...

I assume this is some bot or form reply, but please try to at least try to summarily read/parse my comment before answering. As is clear from my comment, unless extensions are able to cause such issues with the browser UI itself (which I thought was not possible with the move to WebExtensions), I don't see how any of them could cause the reported problem. Also, as I also stated, I already attempted to repro it in a factory fresh clean Firefox profile in a separate, clean VM instance; however I have no reliable way of triggering the problem on-demand as it happens seemingly at random, often for long stretches of time.

Also, when I was able to get it to repro, I disabled all those extensions and reloaded, and the problem still persisted.

jscher2000 said

It's not Markdown, it's wikitext from back in the day.

Ah, thanks; I figured it might be something like that but there was zero indication in the UI or anywhere so I wasn't going to waste my time guessing.

jscher2000 said

Are you docking on the right/left, or floating the tools in a separate window? My only thought about restoring the display when it happens would be to change the docking to the bottom and then back to your preferred position. No idea whether that would help.

Good thought; however, I can confirm it doesn't fix the issue.

jscher2000 said

There's a board for discussing DevTools over here (not part of Support), and they might have seen this or need to know about it: https://discourse.mozilla.org/c/devtools

Okay, thanks—I looked over there and didn't see anything like it, but I'll post this over there when I get a chance. Thanks!

Modified by WIDEnet