I have the next situation:
COM1 is connected to a terminal-line of a CP/M computer: works good.
COM2 is connected to a modem: works good
COM3 is connected to a MS serial mouse 2.1: does not work.
COM1 en COM2 are configured with normal IRQ's and I/O. COM3 is using IRQ10.
In device-manager no conficts are shown. Everything looks good. Even the MS mouse is correct detected. But the mouse will not function.
Removing the ports and re-detection of windows95 didn't solve the problem.