Because the system records the position in the source list, such as Activity1, SAT is at position 01 in the system,. If you modify the list, add Game and the position is above SAT, it will show the position of 01. The result is that Activity1's source is also Game (because Game is at the 01 position now). That' why we suggest that the source list of the projector needs to be completely entered into the three source items of SAT, Game, and Blu-ray. and you can see the operation video for reference: https://www.youtube.com/watch?v=TFUja-P0TAM