I very much like the tab function 
thank you!
Thanks, but can you clarify what you mean by tab function? We didn’t change anything there (though there is one report that they are unusually thin?)
Well I found that when you duplicate a file it is there in the same open file. I never noticed that before. So I thought it was new.
Oh, no - that is quite not intended! (It looks like this was an issue where using newer tools to build Hype erroneously opted the app into this functionality)
While I like the idea of these tabs in general, Hype wasn’t really made with them in mind and it wouldn’t surprise me if it causes problems. I will be looking into it more.
So not use duplicate for the moment, but ‘save as’
Well, those should technically be okay - but you may want to change the “Prefer tabs when opening documents” setting to “Manually” in the System Preferences Dock pref pane. I’m not yet sure what problems may arise beyond a guess that the other post may be related. More details as I find them…