Ron,
I can draw anything you want in CAD. I just never fooled with the screen designer ( i will / want to, but just have to manny irons in the fire ).
A cancel button would be fine to cancel an Arc move.
You can get a full circle ( very close circle ) out of the arc: ie
G1 X0 Y0 feed move
start arc
G1 X1 Y1 is 2nd point
now for the last move use X=1.0001 and Y=1.0001 (or -.0001 from the start / .9999 )
end arc
Just a work around.
Radio Shack sells a USB video camera for $19 ("GIGAWARE" and it works if you don't have one). I have
some high resolution ones but they will not work. Was trying out the XBOX control last night.

Hmm....wide screeen TV monitor, game control, comfortable chair.....using CC can turn out to be very
relaxing!

I would prefer to have the video screen as i have shown it. Just my reasoning, but, it keeps what you need to
do what CC was originaly meant to do all on one screen. The feeds want to be kept on the main screen along
with the DRO's. Besides just picking points, you may want to actaully be doing a complete code file.
Going to another screen breaks your thought pattern / may be a distraction. These are only suggestions
for kicking around. Everybody works differently, I just like Chocolate better than Vanilla.
BTW the tab brings up a blank partial screen.
I figured the biggie wouldn't work but at least we know. That said, then CopyCat stays as first intended.
RICH