code: def showEvent(self, event):
          
          super(XView, self).showEvent(event)
          
          # record the visible state for this widget to be separate of Qt's
          # system to know if this view WILL be visible or not once the 
          # system is done processing.  This will affect how signals are
          # validated as part of the visible slot delegation
          self._visibleState = True
          
          if not self.isInitialized():
              self.initialize()
          
          # after the initial time the view is loaded, the visibleStateChanged
          # signal will be emitted
          elif not self.signalsBlocked():
              self.visibleStateChanged.emit(True)
              QTimer.singleShot(0, self.shown)
docs: Sets the visible state for this widget.  If it is the first time this
          widget will be visible, the initialized signal will be emitted.
          
          :param      state | <bool>