ID : add shortcuts to change ui arragement

ID : add feature to change ui arragement (simple / multi window compliant)
by a sequence of keys ctrl+1 / ctrl+2 / ctrl+3 , user can access to stored ui disposition.
user should have also the possibiliy to save ‘at any moment’ a ui dispo

Initial UI disposition could be : beginner / let’s draw / let’s animate / expert mode(?)
(for each single and multiple mode)

Goal : Progress on Synfig needs to contextualize the action of the animator

Edit / i have already posted something similar … but anyway, feel i want that a lot :wink:
let’s do it oneday by myself ? :slight_smile:)