What it's still missing at today in Kdenlive is the option to use an external monitor while you are having your video overlay on the source and program windows also.
You can just choose where to watch your video overlay: or inside the window or on the preview screen.
For which concerns the option to use more monitors for the application, now is already possible to display Kdenlive on 2 screens and to save the workspace in 2 ways:
- the first is by detaching panels from the main window and by dragging them on the secondary screen but when I tried to do it I found that it not too smooth arrange and resize them
- the second is to resize the main window for fitting all the screens but, in this case, you can't remove the application bar by maximizing the window because if you do it the window comes back in one screen only.
I guess that if Kdenlive can be displayed on 2 or more screens and with a fullscreen preview which works simultaneously to the application windows will be perfect.