Gnats 5271: Removing a Unit Scheme exception doesn't generate a callback on effected slots.

Gnats 5271: Removing a Unit Scheme exception doesn't generate a callback on effected slots.
Phil Weinstein, CADSWES, 2-15-2013

The following diagnostic code (see the "std::cout" statement) shows callbacks on a slot when a Unit Scheme "exception" is added for the slot when operating the slot's configuration dialog.

But no callback is received when removing that exception in the unit scheme editor.

int ScenPlayboxConfigDlg::InSlotWids::slotCallbackHandler (
                                                       CallbackType cbType,
                                                       CallbackData* cbData,
                                                       void* /* clientData */)
{
   static const char* mname (
      "ScenPlayboxConfigDlg::InSlotWids::slotCallbackHandler");

   SlotStatusChangeData* slotDat =
      dynamic_cast<SlotStatusChangeData*> (cbData);
   const Slot* slot = (slotDat ? slotDat->slot : NULL);

   std::cout << mname << " ("
     << (slot ? qPrintable(slot->getCompleteName()) : "SLOT?") << ") "
     << callbackTypeStr (cbType)
     << std::endl;

   switch (cbType)
   {
      case SLOT_DELETED:
      {
         if (_slot && rwAssert (slot == _slot))
         {
            deleteSlotCallback();
            setSlot (NULL);
            _dlg->saveConfig();
         }
         break;
      }

      case SLOT_NAMED:
      case SLOT_USRUNITS_CHANGED:
      case SLOT_SCALE_CHANGED:
      case SLOT_PRECISION_CHANGED:
      case SLOT_FORMAT_CHANGED:
      {
         updateWids();
         _dlg->saveConfig();
         break;
      }
   }

   return (true);
}