Window XXX is a temporary window without parent, application will not be able to position it on screen.
Running gnome-shell master and mutter master, every time I launch an app from the dock this appears in the log:
Gdk-Message: 14:48:39.324: Window 0x55d553c65200 is a temporary window without parent, application will not be able to position it on screen.
Gdk-Message: 14:48:39.325: Window 0x55d553c65200 is a temporary window without parent, application will not be able to position it on screen.
Gdk-Message: 14:48:39.325: Window 0x55d553c65200 is a temporary window without parent, application will not be able to position it on screen.
Gdk-Message: 14:48:39.325: Window 0x55d553c65200 is a temporary window without parent, application will not be able to position it on screen.
Gdk-Message: 14:49:29.645: Window 0x556a5beb5270 is a temporary window without parent, application will not be able to position it on screen.
Gdk-Message: 14:49:29.645: Window 0x556a5beb5270 is a temporary window without parent, application will not be able to position it on screen.
Gdk-Message: 14:49:29.645: Window 0x556a5beb5270 is a temporary window without parent, application will not be able to position it on screen.
Gdk-Message: 14:49:29.645: Window 0x556a5beb5270 is a temporary window without parent, application will not be able to position it on screen.