To prevent a display application from making a video present source the primary view, you should mark the source as removable. To indicate which sources are removable, you can specify a DWORD Plug and Play (PnP) value in the registry named RemovableSources.
Note You cannot mark source 0 in the DWORD bit-field value as removable.
The nth bit in the bit-field value specifies whether source n-1 is removable. For example, to mark source 1 as removable, you can add the following line to a display miniport driver's INF file:
HKR,, RemovableSources, %REG_DWORD%, 2 ...
For more information about installing display drivers, see Installation Requirements for Display Miniport and User-Mode Display Drivers.