Fullscreen Projector Program/Preview difference?

[onscreen]

Does anyone know the difference between Preview and Program full screen projecting?

You only get the option for Program full screen projector if you right click the tray icon, I can't see this option documented anywhere to find out what the difference is, anyone know?

 

[lebaston100]

There is only a difference if you enable Studio Mode in obs. Preview is on the left and Program on the right. If it's enabled you also get the right-click menu for the preview projector where the preview is inside the main window.