We are considering various options here including what you have suggested, a tabbed interface, and an undock option. This could also be used in Compose context.
My biggest issue with the Runbox 7 version is that I cannot read messages full screen or maximized. Thus I find myself going back to the legacy interface where I can still do so.
This is almost a deal breaker for me, I really dislike being forced to read my message in 1/3 of the browser window.
Just letting us open messages in another tab in our browsers like we can do in runbox 6 works great for this. Simple solutions are the best approach most of the time.
Right now, in runbox 6 I open a new message full screen in a new tab just by clicking the middle button in my mouse.
You could imitate this behaviour with double click like suggested above.
Your own tabbed interface or an undock option are always going to be clumsier than that.
The main problem I see with runbox 7 (aside from getting stuck with the index refreshing very often) is how many clicks everything needs and how much moving around the mouse is needed to do very common tasks.
Get someone in the team to really use the webmail as main mail client and they will notice very soon, I promise.
Also, if the message is viewed in Full Height, the “X” is on the far right side of the screen that takes you back to inbox. Runbox 6 and Gmail have an arrow or “inbox” icon right above the message you are viewing on the “move/reply” icon line.
Maybe add this as well to runbox 7 so we can view full height and return easily?
I dont mind the reading in the 1/3rd screen. Actually like it. What is a pain in the neck though is upon reading the file it would be nice is when I delete the read message that the screen would populate with the next message