I'm using VFP 7.0

I have a button in a container on a form.
(I've abbreviated this code, but I think I have what's pertinent)

button.method()
  lo = NewObject('HyperLink')
  lo.oCreator = this          << this is the line that causes the problem
  this.oHyperLink = lo
endproc

After creating the object, Thisform.Release() is skipped - no error - no nothing. When I debug, the trace window points at the line but then skips to the next line.
If I take out the line, then it works fine.

I can't see that it's any different than the oHost property in SetObjRef.prg.
In reality I'm adding the oCreator property inside a modified SetObjRef in the exact same manner as oHost is created.

TIA