jPV wrote:

1) An easy way is to select "Jump to Screen -> New" from the MUI popup menu gadget in program's window border. It always opens in enhanced mode and clones the resolution from Ambient. Open and save program's MUI settings to save it to permanent use.
MorphOS3_jPV_Newscreen.png

2) More configurable method is to open program's MUI settings, select Screen tab, and create a totally new screen definition there. You can edit screen name and title to suit your use (program name or so), select any resolution and depth, enable or disable enhanced mode etc. In many cases this is a better method, because you can save graphics memory by not using enhanced mode for the screens which you're going to use for full screen apps only or so.

And yes, then you can switch screens wth lamiga-m (lcommand-m), or by clicking the screen depth gadget (left click switches to the next screen, right click gives you a menu where you can select any open screen).