UPDATE
Reverted to version 1.0003 and ran a few programs. No jumping during slow continuous jogging, and when I switched back and forth a few times between UCCNC, Fusion, HSM Advisor, Chrome, etc. it didn't disconnect or lose the step function when I went back to UCCNC.
The UCCNC built-in plugin worked fine, no issues observed.
To clarify my earlier post, the 'disconnect' wasn't full disconnection of the joystick. Just that all step buttons quit working as intended; if I pressed the 4-way x/y step button at an angle (both at once) both axis would move in continuous mode at the same time. Same thing for the Z button - press the Z-step button and nothing happens; hold it down and press another step button and the Z starts moving in continuous mode (and 'safety' triggers not pressed).
Note - Keyboard and on-screen step jogging also failed to work - so this problem may have nothing to do with Eric's plugin but is some glitch in UCCNC or my particular combination of Win8 & UCCNC.
The joysticks and the other buttons still worked during this situation. Only solution was to close UCCNC and re-start.
This wasn't an exhaustive test, so no conclusions. I'll continue with the earlier version for a while and report back what happens.
Regards,
Spumco