As mentioned in the Tab Groups documentation, if you accidentally close a tab group an "Undo Close Group" button appears which lets you restore the tab group.

However, the button disappears as soon as you open a tab from another tab group. Fortunately you can still restore the tabs from the closed tab group via the Firefox > History > Recently Closed Tabs menu (unless you have turned History off completely or are in Private Browsing mode).

Hi Brian. There were no tabs saved in Recently Closed Tabs.

I am really astonished that designers at Mozilla could implement such a badly designed feature. If you save a group of tabs, it disappears from the view and there's no way to see it again. If you close it, it disappears forever. So unrespectful, I am furious! What's the point of having an undo feature if people are unable to understand what they have just done? Why not display all the groups of tabs in a corner on the grey background so they can be reopened at any moment easily? Groups of tabs should be an alternative to bookmarks, a better way to save pages and read them alter as it keeps things in context, rather than throwing it into a scaring container like the bookmark manger. I want to read this but not now, I want to keep it here beside so I have them ready. Do you ever work with scenarios at Mozilla? I think you should consider it. Also, I would add that this feature should work so the tabs saved as a group are not reloaded all the times, in order to save memory. They are saved as bookmarks and only loaded when the group is reopened. Also I found just incredible that the tab group does not appear in the history and in the main bar if I type it, so really, you can loose all the pages that you had opened and never be able to retrieve them!! I will never use this feature and to be honest, after installing a few addons to Chrome, I see no reason to use firefox any more. I can search as I type, manage sessions and crashes, block ads just the same as in firefox, and the memoery usage seems to be better.

As a summary, here are my recommendations so this tool can be improved and become more useful:

• tabs across multiple windows should be displayed together. If I create a group and another group in two separate widnows, I should be able to see both when I click on the panorama button
• option to save memory: you might want to have many tabs available without a large amount of memory being used. Memory is an issue in general with firefox. At least one should be able to restart the browser without all tabs being loaded until a group is opened
• Allow to save a group of tabs as bookmarks (save as a group, but keep them there, so they are still handy)
• Rather than the almost useless undo button, it's better to inform people that if they attempt to close a group, they would lose all the tabs in the group permanently. Alternatively, open an overlay that gives two options, save as bookmarks or close without saving
• Save tab group name in history so a group can be reopened if closed accidentally

Thanks

Personally me even didn't push close-button. I just tried to enter edit-name-field but suddenly got closed group and closed tabs. No any "Undo Close Group" button didn't appear. It was some accident, it's clear. But where is any means to restore group or tabs?!!! These disappeared tabs were not in "Recently closed tabs". They are not reflected in history. They disappeared without any trace (at least in user interface) and I'm agree with the opinion that this highly mean situation was absolutely unexpected especially from Mozilla. Tab groups is a great feature but only in case if it doesn't lead to information lost! May be somebody could point where can I find URLs of tabs of lost group?

Absolutely agree with humaneint "...Rather than the almost useless undo button, it's better to inform people that if they attempt to close a group, they would lose all the tabs in the group permanently. Alternatively, open an overlay that gives two options, save as bookmarks or close without saving Save tab group name in history so a group can be reopened if closed accidentally..." although suppose that "undo button" is not excessive but it must not disappear just after any following action... Generally think that such restore-features are already obvious "standard" classic features for any modern soft unit... It means that their absence is pure omission. Hope soon this bug will be repaired ...