WARNING: If you use large numbers of tabs this add-on will frequently destroy the organisational structure of the tabs you have sorted into different panels when closing and reopening a browser session, requiring you to potentially reorganise large numbers of tabs or close the affected browser windows and attempt to load a saved snapshot of them, wasting a lot of your time.

As other reviewers have already mentioned, this problem doesn't appear to be an issue if you only use small numbers of tabs.

I tried this add-on after being a long time 'Tree Tabs' user (which handles large numbers of tabs reliably) and was hoping Sidebery would be a potential replacement with more QoL features.

Unfortunately Sidebery's inability to reliably save and restore browser session tab structures with large numbers of tabs means I would not recommend this to anyone who browses with large numbers of tabs.

Hopefully this issue can be fixed as Sidebery has a lot of good things going in its favour (e.g. clean UI, snapshot save system, panel sorting, containers) however until this critical issue is fixed the user experience is frustrating and wastes their time.