@jaunny
Hi, if I open a session as new window all workspaces are included if I save from the main tab.
Closing with X don't move the workspaces into the existing window.
"open workspaces as tabs" does not crash Vivaldi 6.2.3105.51 but it open it the same as new window, all workspaces are there.
I don´t have an old session to test this, please wait id other user can reproduce this, then you can report a bug to the Vivaldi bug tracker.
The new panel for sessions and the auto save is experimental but the session feature is the same, I tested this with enabled session panel in Experiments and disabled panel.
Cheers, mib