The TSR source code, documentation, and executable program in the ZIPfile DI1311Z.ZIP attached to EDN BBS /DI_SIG #1311 lets you add mouse control to any PC application.
This Software Short listing is too long to reproduce here. You can obtain the listings from the Design Idea Special Interest Group on EDN's bulletin-board system: (617) 558-4241, 300/1200/2400 8,N,1. From Main Menu, enter ss/DI_SIG, then rknnnnz, where nnnnz is the file referenced above.