I resolve this problem by disabling the addon named Abduction! Check your addons :)

Thanks a lot! It was caused by this addon. I tried turning off ads in the settings of this addon and tab groups is working again :)

Thanks sphax3d -

How did you go about finding which Add-On was causing the issue (how did you even know it was an Add-On that was causing this issue) & how long did it take you to find out which Add-On was causing the issue?

I have used tab groups before with great success. Recently I can type in the 'group name' but the name does not show up on tab group any longer once I minimize the group. I do not have the Abduction add-on... I checked. Any ideas? Thanks

I do not have Abduction add-on enabled. Could it be something else that causes the group naming to not appear on minimized tab?

I have the same problem. I can't invoke the tab groups panel, not by clicking the toolbar icon, not by pressing the keystroke combination (Ctrl-Shift-E). Deactivated all extensions but still doesn't work. Using FF 12.

The strange thing is that the Tab Groups mechanism works fine on a new window. But in the main window where I have more than a hundred tabs open, it doesn't work. Please, help!

I have the problem and an unresponsive scrip that seems to be related. Please see the attached.

I had this problem and eventually resolved it by disabling the addon AutoGroup, which was the addon I had most recently added and which had something to do with tab groups, so it seemed a likely culprit. Sure enough, as soon as I disabled it the keyboard shortcut started working again, and just for good measure I reenabled the addon and immediately upon restarting got the scene in the picture below. So for me, AutoGroup was the clear culprit.