Action of double click on file display

Is it possible to assign more than one command? (close 2 toolbars and open 1)
something like CTRL+SHIFT+any letter?

You can use a user-command or script-command to run multiple things, or different things if a hotkey is held down, on that event.

User command seems to be what i wanted but don't know how to put all those commands on only 1 row

I already have a button with

Toolbar NAME=Preferiti
Toolbar NAME=Libreria CLOSE=all
Toolbar NAME=Ordinamento CLOSE=all

and hotkey is Ctr+Shift+P

But how can make this action to be done with double middle click? what do i have to write there?

The purpose of user-commands is to let you define a new command (e.g. "MyCommand") which you can use anywhere that the internal commands are used, and which can then run multiple commands when you run it.

So put your three line command into a new user command, and then specify that user command as the thing to run.