Sticky Window Containers — jchronakis

Firefox extension that makes all tabs in a window to "stick" to the same container that the first tab. Effectively making windows behave as "single container windows".

This is useful for people like me that assign a whole window to an activity (e.g. work or personal)
and further move those windows to each own workspace.

The extensions achieves that by opening all tabs to the same container as the first tab in a window.
To e.g. create work window, open a window and set the first tab to "work" container.
All subsequent tabs will open in the same container.