def __init__(self, scroll): super(EventsWidget, self).__init__() self._scroll = scroll # Timeline background color palette = self.palette() palette.setColor(self.backgroundRole(), QtCore.Qt.white) self.setPalette(palette) self._tracks = [Track(parent=self)] # List of tracks self._pointer = TimelinePointer(0, self) # Timeline ( greenline ) self.tracks_height = 60 self._first_track = self._tracks[0]