This gives the mode of the custom screen to open.
The mode is as show in the Screen Mode requester - case is ignored (e.g. "PAL:Low Res"). This parameter is not changed by Requester loaded projects.
The name of the screen must be given by the PUBSCREEN parameter. The depth is given by the CUSTOMDEPTH parameter. The screen will mostly clone the Workbench, but other colours will be set up as a grey scale.
It can be changed using the menu item, a requester is displayed allowing the input of the screen mode, but any change is ignored until MPMorph is reloaded.
The default value is nothing which means do not open a custom screen.