@ AriAhrendt answer What I request is to bring back the Studio One v2 zoom behavior. I personally find it annoying to have to reach for my keyboard just to open the musical editor with the previous zoom state. Especially when performing or having only one hand free.
I really don't understand why an important action like "Open editor", we do thousands of times when working on a song with a detached editor isn't under our mousing fingertip and is replaced for "Show me all content of the clicked event in an overview". Especially since the overview is already there in the arrangement. I work with relatively short parts, but I could imagine when working with long parts the current v3 behavior feels even more as a regression because the editor's view won't tell you much more over the arrangement view.
Mind the image below of the Studio One 2 behavior. After I opened the detached editor the first time (with double click) and zoomed to the preferred zoom level, I can close the editor, open the editor with double click, close it again and open it again with double click, all respecting the zoom level I've set. When I finally double click again when the editor is open, it zooms out to fit. Very functional and well thought out!
That's the request!
On a side note: Another downside of using a KC over LMB when working with a detached editor is when opening several Instrument Parts residing on different tracks with a KC (like F2) only shows the last selected part in the editor. So you have to open the list editor and enable the view of the other track. While opening on double click instantly shows all parts.