The extension window is partially empty.
As in the title, the extension windows have blank fields for a while. I'm using ubuntu, and this has been happening since the new update that changed the look of Firefox. This happens with all add-ons. The bug can be seen in the attached image.
Alla svar (3)
Some add-ons have been known to cause such issues.
Start Firefox using Troubleshoot(Safe) Mode {web link}
A small dialog should appear. Click Start In Troubleshoot(Safe) Mode (not Refresh). Is the problem still there?
The problem is that, in this mode my extensions are disabled. (i don't see the way to turn them on back)
Is the problem gone in Troubleshoot(Safe) Mode?
If so, it could be the work of one of your add-ons.
Type about:addons<enter> in the address bar to open your Add-ons Manager. Hot key; <Control> (Mac=<Command>) <Shift> A)
In the Add-ons Manager, on the left, select Extensions. Disable a few add-ons, then Restart Firefox.
Some added toolbar and anti-virus add-ons are known to cause Firefox issues. Disable All Of them.
If the problem continues, disable some more (restarting FF). Continue until the problem is gone. After, you know what group is causing the issue. Re-enable the last group ONE AT A TIME (restarting FF) until the problem returns.
Once you think you found the problem, disable that and re-enable all the others, then restart again. Let us know who the suspect is, detective.