>>>>Frequently after running a form, when I go to the pj to modify one
>>>>of the classes used in the form (or the form class itself) I get the
>>>>error "cannot modify class in use" (syntax may be wrong). I spent
>>>>many hours trying to figure out where it was in use, but then
>>>>discovered that I can modify a sub-class of the forbidden class, then
>>>>then forbidden class can be modified.
>>>>
>>>>Example:
>>>>
>>>>run client.spx
>>>>modify class frmBase --- error
>>>>modify class frmData --- subclass of frmBase used by client.spx
>>>>close frmData
>>>>modify class frmBase --- works fine now
>>>>
>>>>What am I missing?
>>>>
>>>>TIA
>>>
>>>Correction
>>>
>>>Example:
>>>
>>> run client.spx
>>> close client.spx
>>> modify class frmBase --- error
>>> modify class frmData --- subclass of frmBase used by client.spx
>>> close frmData
>>> modify class frmBase --- works fine now
>>>
>>> What am I missing?
>>>
>>> TIA
>>
>>Addition:
>>
>>I have tried disp memo, list objects, clear all, close all, everything possible.
>>There is no object. If there were, I could not modify frmData. And I don't
>>do ANYTHING AT ALL between modify class frmDATA and modify class frmBASE EXCEPT
>>closing frmDATA.
>As far as I can understand your frmData is based on frmBase and is open at that time, right ? If so frmData is already using frmBase class.

Nope.
after running and releasing the form, I try to modify frmBase, but I can't
because it's in use (it isn't but VFP5.0a thinks it is). In order to get VFP
to recognize that it's not in use I just modify a sub-class of frmBase (any one
will do), close it then try to modify frmBase again, and it works fine.