To not waste more screen space than necessary, you now have the option of hiding the Output view and still being notified about the command success or failure.
If a command fails or produces some warning messages, you will see the exact invoked commands and their output in a dialog, easily disposable with ESC.
In case the command succeeded or you have opted for not seeing certain warning messages you may see instead an automatically-hiding notification.
Certain commands, e.g. Stage, will not show any dialog at all.
To see the full output again, use Window | Output.