Phantom element in PCB when performing DRC

Question

I have a PCB that shows a clearance error when performing a DRC. The DRC identifies a thin item that does not seem to exist in the actual PCB. I have tried individually and group selecting but this does not seem to work. The phantom item lies on a polygon outline. If I move the polygon outline the clearance error is no longer there.

clw · Accepted Answer

Yep, I'm fully aware of that.

The problem is now solved.It turned out to be two adjacent polygons for different signals on the top layer with the same rank. The clearance error flagged turned out to be where the outer bounds of the isolate loci of one polygon interfered with the adjacent one. When the polygons were moved closer the DRC clearance error was more apparent, rather than a minute element of the periphery. Changing the rank of one polygon fixed it.