How do I add another to the Workspace menu ?

How do I add an option at this location ?

@Dennis thank you for the discussion, this is actually a toolbar item, where multiple items are put under the same group and result in a context menu.

You can register your own toolbar item to this group like so:

@vince-fugnitto Thanks for your reply,But I have tried many ways, but there is still no solution. Could you please help me have a look again.

@Dennis Are these methods actually called? Have you bound them correctly?

In your case, your binding should look like this: