Brian and I are continuing to beat on this, and finding increasingly smaller, and more obtuse,but nonetheless significant, issues. There is still an apparent problem with VB scripts hanging around, and causing problems. Brian is working on "instrumenting" this, to track down the root cause. We've tracked down some unexpected side-effects of some functions (like the fact that sending Mach3 a Continuous Jog Stop (OEM buttons 334-339) will cause G0, G1, G2, G3, G31 to misbehave. If you have a VB button, it is quite easy to get two instances of the script to run simultaneously (not good...), with often odd, and unpredictable, results. I believe these things, in aggregate, go a long way towards explaining the capricious and unpredictable nature of screenset and VB programming in Mach3, so I think we'll all be much better off once they're cleaned up.
My machine did something truly bizarre a few days ago - It got itself into a mode where, when doing a probe in Z, instead of doing the correct sequence (fast probe down, retract, slow probe down, retract) it would do a fast probe UP a short distance, then RAPID UP into the limits! Even a re-start did not fix it! A few hours later, it started working right, all by itself.
Regards,
Ray L.