1.3.7 . Activating closed all my tabs yet increased RAM (not memory) use by 80MB. Opened as another window, which only made it more difficult to use because it was not possible to switch windows. The Tab Group window insisted on always being on top. Would work better as a tab. Kept on opening Google, even though i avoid Google. That is configurable. Color scheme is bright, independent of user browser configuration.

Nice try, but still no replacement for the old Tab Groups.