I noticed several times that Mach3 (with an Ethernet SmoothStepper) went crazy and kept jogging after hitting an arrow until the machine hit a limit. 

Upon testing, I realized this is coming from holding the shift for Rapid, then releasing the shift BEFORE releasing the arrow.  After releasing shift THEN arrow, the machine keeps doing a rapid without any input.

Was this an intended feature?  If so, how do I disable it?

If it's a bug, how do I fix it?  It's super-dangerous, IMHO.

This is a known repeatable bug in Mach 3 unrelated to the SmoothStepper.  I have a different motion controller and it does the same thing.  I understand it even happens with the parallel port for some people.  First time it did it I was trying to teach my 11 year old grandson how to pick up an edge.  It ran away breaking off the edge finder against the vise, and then ran until the X axis hit the limit switch, which on my machine actually disconnects power from the stepper drivers.  So it didn't crash against the ends stops and break anything.  However it scared hell out me and my grandson thought he did something wrong so he won't work on the machine with me anymore.  I built it to teach him about building things, so that is a real bummer.  Keep your hand on the big red button if you use the shift key!

It's a known bug in Mach 3 and won't be fixed by ArtSoft... actually any problems/bugs/improvements with Mach 3 won't be addressed now that Mach 4 is released. ArtSoft is having enough problems trying to get Mach 4 to work right and expecting people to pay $200 for the privilege of using a half developed product. Hitting the E-stop will stop the locked on jog function.  

WOW!   That's surprising.  Does it happen in Turn as well?  I use shift/arrow keys multiple times during every session on my lathe and have never had the problem.  Maybe I just naturally hold down the shift key and therefore don't see the problem.  Thanks for the heads up.  I'll need to do some testing now.

It is either a problem with the pugin or the way the plugin handles things from Mach.

I am sure this problem was flagged up before, probably by Gary and I tried it out on the Chiron with the CSMIO/IP-A and got it. I contacted CS-Lab and they had it fixed within a day or two. If this is not the same problem that CS-Lab fixed then it is very similar. In any case I have just this minute tested on my Chiron and it worked as expected, no run away at all.
Hood

I have also fired up the Beaver mill for the first time in a year or more and tested it. The Beaver uses the USB SmoothStepper and there is no problem as above. I tried, like I did on the Chiron, with both releasing the Shift key First and Last and neither run away. Releasing the shift first  and the axis continues to jog until the arrow is released, it then stops. Releasing the  arrow first stops the jogging right away.

Maybe a plugin or Mach version issue or maybe it is something I am not doing exactly right to see the issue.
Hood

I've duplicated the problem when I was using the PP to Gecko 540 then again when I went to ESS SmoothStepper to 540. So it's not a plug in problem. I just learned not to use the shift and arrow keys to jog and chalk it up to another Mach 3 unfixable bug.... one of many.

Then there must be more to it than simply releasing the Shift key before the arrow key. I have tried on 2 machines and it does not happen.
Tell me a repeatable way to get it to happen and I will test, until then I say it is plugin or the way the plugin interprets Mach.
Hood

What version of M3 does this go nutty on ? May have been fixed in later releases. ? ? ? ?
I've never seen it on 3 machines here.

Russ

I have been running Mach3 for many years now, and NEVER heard of this.... (Cuz I've never had the problem)
I use shift arrows all the time.

But now that I know about it, I'm sure it'll happen next time I flash up the machine...
Curious as the the version as well...