So, these days I had less time than usual so I couldn't do what I had in mind like discussed in #553 (closed).
Honestly, if you allow me, I don't like very much the current solution. It bothers me a little.
But I didn't find another solution so if you have some suggestion...
(last attempt) The current UI is roughly like :
What I wanted to do :
Each views handle their own toolbar.
But I always have difficult to anticipate so I don't know if what i had planned was going to do more good than harm.