>Am I correct that this only happens for one class in one class library? Or are their child classes that fail as well?
>
>>>I understand the problem very well. PEM Editor crashes VFP in that class.
>>>
>>>Can't you just close it and not use it when you need to work on that class? ... and then re-open it later?
>>>
>>I can, of course.
>>In fact it is a matter whether I choose to close it or uninstall it. To me the effort will be the same, one click on a customized button on my toolbar.
>>
>>But I will prefer to uninstall it, just in case I forget and accidently "Add new" property or method in the mid of my busy coding... yes in this case I am referring back to Noami's problem.

In my case:
There is a class called VPMDataHandler in a classlib called VpmDataHandler.vcx, it does not cause any problem to PemEditor.
But a subclass of it named ProDataHandler in another classlib ProDataHanlder.vcx will cause PemEditor to crash with buffer overrun.
In fact any subclass I create based on that VPMDataHandler or its subclass will buffer overrun PemEditor.