Show color-picker dialog to select color.

        Qt will use the native dialog by default.

def onColorPicker(self):
        """
        Show color-picker dialog to select color.

        Qt will use the native dialog by default.

        """
        dlg = QtGui.QColorDialog(QtGui.QColor(self._color), None)

        # if self._color:
        #    dlg.setCurrentColor(QtGui.QColor(self._color))

        if dlg.exec_():
            self.setColor(dlg.currentColor().name())