I suspect what you are seeing with the DROs running on a bit is there is a slight delay to its operation (at least when emulating) , so in that respect it is not like pressing the stop as that is immediate.

Hood

You could be right, the longer it is not having an active machine here at the house that runs MACH3 the more I seem to  forget about how it is suppose to work(;-)

Probably about time to sit back and watch the newbies play with it .

(;-) TP

I almost responded to the original post, glad I didn't though. Was going to suggest a macro instead.
Emulating, looked fine here too, but made me wonder what the heck its function is actually intended to be. ? ?
I picture a mill or robot with an enclosure.
Open the door or gate while a program is running and it stops (instantly) most likely loosing pos., close the door and it resumes ? ? no reset requested ? ? ?
  Imagine a robot and the door closes behind you, you'd be eaten alive.
Seems like it should just prevent the activation of any code or program cycle while IN #1 is active, otherwise EStop !
As far as disabeling jogging, while the door/gate is open (In 1 active) you might want to do some work with the pendant or what not. So you would NEED jogging enabled.....but no chance of a Cycle Start.
Any idea of its intended function ?
Russ

I think the original intent was IF the safeties were not armed THEN the machine would NOT run the G code program. That part still is there. I think the back end got added on as an after thought. If you open the door the machine stops with Estop.

Probably the best option as you cannot really depend on feedhold to always stop quickly. So you cannot stop the spindle UNTIL motion stops. So there is a period of unsafe condition after opening the door.  I think running with the buffer you have little choice but to either run the buffer out OR dump the buffer and stop instantly.

AND you have to remember Mach3's  hobbist background. I don't think it was a top priority at the time.

Just a thought, (;-) TP

Mach4 will be interesting to see on a machine, Feedhold is supposed to be instant, fingers crossed
Hood

I think the original intent was IF the safeties were not armed THEN the machine would NOT run the G code program. That part still is there. I think the back end got added on as an after thought. If you open the door the machine stops with Estop.

The afterthought was with good intention then, but must not have been verified to work properly, cause it dont do that.
It just does a slam bam hybrid feedhold, then resumes ... and if the spindle is running, it don't even stop. (sim)
Seems to be a dangerous liability the way it is. Surprising.
I would not recommend using it for obvious reasons. 
Nasty bug.