This message is specific to version 2.1, or higher, of the OS/2 operating system.

This message is used only by applications that wish to remap mouse messages in the PM input queue. It is not recommended for general application usage, and applications should NOT process this message in their window procedures.

param1
     ULONG  ulPhysButton    /*  The physical button number (1, 2, or 3). */

param2
     ULONG  ulMappedButton  /*  The button to be mapped to (1, 2, or 3). */