Hello Jeff,
The resolution you set in your game settings determinde the base resolution of your game.
Scenes which are larger will get scrolled, scenes which are smaller will render black at the left "free" space.
So to achieve a windowmode for your 1920x1080 Pixel game resolution, you dont need to change this base resolution. You need to switch to window-mode and resize that window.
To toggle between fullscreen and window mode there are two ways:
Keyboard: ALT+Enter
via Luascript: toggleWindowMode()
to set the window size:
via Luascript: setWindowSize({x=1280,y=720})
These both scripts can be used inside an "Execute a script" action part.
Note that details in your backgrounds get lost, when you resize your game to a smaller resolution than intended by the game settings.
When you want to remember if your game should start in wondow or fullscreen mode, you need to create a script, which fills the resolution/window settings into your config.ini file
(forum destroys the link. Copy it with the (CMS) included)
kind regards
Sebastian