WireCut's Keep All option not working

Rhino Rhino for Windows
1

I create a new file (using v7, fully patched), create a rectangular surface (plane cmd), create a line, and try to cut the rectangle into two pieces with the WireCut command. The Keep All option is set to Yes but one of the sides of the cut is always deleted.

I have been using the WireCut command for years and never had this problem.

2

Yes, I see that with a simple plane. If you extrude the surface into a solid, it keeps all.

Appears to work correctly in V8. I don’t know if the fix might be backported to V7, probably not…

In any case for this simple of an operation, normal Split works fine from the view direction.