Hi, please to look at this question:

* I think that this problem is a bug or limitation in VFP9.
* By this example, I can see that one class defined by the user can't be
* inherited more than one time, because if its occurs the classes are tied
* in the memory, it is checked when I try to edit the classes after inherited
* and VFP9 displays the "Remove classes from memory" message.
*********************************************************************************
Local lo as Classe1
lo = NewObject("Classe1")
lo.newClasse2()
Release lo
*********************************************************************************
Define class Classe1 as Abstract1
  Procedure newClasse2  as Boolean
    Local loClasse2 as Classe2
    loClasse2 = NewObject("Classe2")
    Release loClasse2
  EndProc
EndDefine
*********************************************************************************
Define class Classe2 as Abstract1
  * If this class specify Abstract1 the classes     will be tied in the memory, because Classe1 specify Abstract1
  * If this class specify Abstract2 the classes will not be tied in the memory, because nobody class specify Abstract2
  * So my conclusion is that we can't specify a class defined by the user more than one time,
  * because it make the classes tied in the memory when I specify Classe1 and Classe2 inherited from Abstract1
EndDefine
*********************************************************************************
Define class Abstract1 as Custom
EndDefine
*********************************************************************************
Define class Abstract2 as Custom
EndDefine

In my application I have problems and I think that thouse problems are because the objects are not cleared from the memory