Shortcut to come back to coding panel

I've look at the shortucts document , however I can't find a keyboard shortcut for coming back to the coding panel.
So I'm asking is there a way to lets say go to projects panel (alt +1) and then  come back from the project panel to the coding panel via shortcut?
If I press alt+1 again it will close the project panel and switch me to the coding panel, but closing the project panel is not acceptable.

Thanks,