Performs a context-click (right click) on an element.

        :Args:
         - on_element: The element to context-click.
           If None, clicks on current mouse position.

def context_click(self, on_element=None):
        """
        Performs a context-click (right click) on an element.

        :Args:
         - on_element: The element to context-click.
           If None, clicks on current mouse position.
        """
        if on_element:
            self.move_to_element(on_element)
        if self._driver.w3c:
            self.w3c_actions.pointer_action.context_click()
            self.w3c_actions.key_action.pause()
            self.w3c_actions.key_action.pause()
        else:
            self._actions.append(lambda: self._driver.execute(
                                 Command.CLICK, {'button': 2}))
        return self