Good to know! I take it this means that I just have to wait for the next update or so?
Yes!
So I closed the window with 25 tabs, 20 of which I was saving for future research so they haven't actually been opened for weeks. There was another window accidentally opened, with only one tab. Now I have NO HISTORY of those 20 not-recently-opened tabs. WHY DOESN'T OPERA ASK LIKE FIREFOX DOES? And HOW CAN I GET MY TAB-LIST BACK?
That's not screaming; it's crying!
This is the forum for Opera beta and Opera developer. If you're using beta/testing versions, you should know things like these are likely to happen.
If you're talking about the stable version, Ctrl+Shift+T only works for tabs so you should find the recently closed window in the Tab Menu at the end of the tab bar.