QtDragon PROBE: understanding popup error message

I am using QtDragon and wanted to probe a hole. I started the inside hole probe with the probe tip roughly centered above the hole. I got the following popup:
 
My PROBE settings were:
 

My questions are: What is "Max travel" referring to? Is that "XY" or "XY TRAVEL" or something else? And where do I find "xy_clearance"?

Where was the source for this PROBE panel located? Maybe, I'll figure it out myself.

Kind regards,
Guido

OK, I found it.
/usr/lib/python3/dist-packages/qtvcp/widgets/probe_routines.py, line 698f:
So, it seems that XY TRAVEL needs to be bigger than 2x LENGTH - LATCH RTN.

Setting XY TRAVEL to 15 and LENGTH to 2 (metric) worked for me.

Choosing the right parameters seems tricky to me. Preferably XY TRAVEL should be small, but OTOH I would like to be able to probe larger hole diameters than a few millimeters.

It might have been nicer if the max travel was calculated based on the length to probe.
ie probe length = 10, max _over_ travel = 5 then anything that moved 15 would trip.