'Launch the associated command to the clicked icon.'

def button_press(self, x, y, button):

    if (button == 1):
        icon = self.get_icon_in_position(x, y)
        if (icon is not None):
            cmd = self.progs[icon]['cmd']
            if cmd.startswith('qshell:'):
                exec cmd[4:].lstrip()
            else:
                self.qtile.cmd_spawn(cmd)
        self.draw()
