code: def resizeEvent(self, event):
          
          result = super(ResizeDetailsMessageBox, self).resizeEvent(event)
  
          details_box = self.findChild(QtWidgets.QTextEdit)
          if details_box is not None:
              #details_box.setFixedSize(details_box.sizeHint())
              details_box.setFixedSize(QtCore.QSize(self.detailsBoxWidth, self.detailBoxHeight))
  
          return result
docs: Resizes the details box if present (i.e. when 'Show Details' button was clicked)