It should be re-created when you start another debug session. I don't think you can close it without shutting down the debug session.
If it's just hidden, and the tool window buttons aren't showing, you can either show the tool window buttons by clicking the square-with-sidebars button in the bottom left. Or use Cmd-Shift-A and type 'debug' to activate the hidden tool window.
(I hope I got the details right, as I'm not on a mac and can't double check)
It should be re-created when you start another debug session.
I don't think you can close it without shutting down the debug session.
If it's just hidden, and the tool window buttons aren't showing, you can either show the tool window buttons by clicking the square-with-sidebars button in the bottom left.
Or use Cmd-Shift-A and type 'debug' to activate the hidden tool window.
(I hope I got the details right, as I'm not on a mac and can't double check)
George, have you found it already?
By 'close' you mean you stopped a debug session and closed a cirresponding tab on the 'Debug' tool window?