Very small detail: just found that Go Opencontainer= doesn't offer the Newtab option.
It's also not in the manual. Where are you getting that from? NEWTAB is a separate argument, not a parameter you'd give to OPENCONTAINER.
(If it works, it's probably for compatibility with commands people may have made in a very, very old version. It wouldn't be the normal way to open in a new tab.)
Yes, that's what i thought also, that it's some kind of separate argument. I got it from a very old context menu item for my collections, in case i want to open the original folder. Must have asked here a long time ago, if it's not standard.