I haven't tried the release of the shift key before the axis arrow, so I can't say. I will do that Monday. Interestingly, I ran multiple parts today and it didn't happen once. It well could be I released the axis before the shift today. This machine has no external controllers, uses a Galil board and no pendant. I think the Galil board is a quality board from what I know of electronics and not a junker from China. It may be a Mach3 bug perhaps. Yes we can merge threads, although I don't know how to do that.