In all previous versions of Cubase you can toggle the mixer open/close with a single key stroke. In C7 pressing F3 first brings the mixer into focus. It requires a 2nd keystroke to close the mixer. Is this intended?
Personally, I much prefer the way it has always worked. Fewer clicks, faster work flow.
But I suppose if you want to use the mixer and it is hidden behind another window, with the old behaviour, it would have required an additional keystroke -once to close it and once more to re-open it with the mixer now being at the front.
OK, yes I can reproduce that, only for hiding the mixer though, and only when, as you say, the Project window has the focus - not the Cubase main window. It seems the first click removes the focus from the project window, then the second click does it’s job hiding the mixer.