I discovered a kind of hack to switch the focus to another Window:
# imagine "view" has focus in window 1, and "_view" resides in window 2, the following will change the focus to window 2 from window 1
_view.window().focus_view(_view)
_view.window().run_command('focus_neighboring_group')
_view.window().focus_view(_view)
_
Now… I wonder if there is some way to “move” a tab/view to another window? I know that I can close the current file and opening it in the other window, problem is that what I need is a clone of the file. So I would like to be able to move cloned tabs to other windows… or clone tabs that reside in other windows… Any hint?