How to add menu to close tab

[Cavin House]

Today by chance I discovered a pretty cool Extension, I tried it, and suddenly its menu appeared under Close Extension.
I don't understand how they can add menu to this section, someone help me clear my eyes and see how to do it
Thank you

[Kukurykus]

I can't understand what you ask for.

[Cavin House]

I have attached an image to the post, I want to add the menu to the close tab as shown in the picture

The language between me and you is not the same, I talk to you via google translate, so please forgive me

[Kukurykus]

Okey, what do you mean by 'Close Tab'?

[Cavin House]

I want to add a menu above the close tab menu in the picture

[Kukurykus]

CEP 11 HTML Extension Cookbook

[Cavin House]

[Geppetto Luis]

I'm sorry I didn't understand one thing you have created an extension and now would you like to add a menu like the one in the picture?

[Cavin House]

yes i am extension i want to add menu in picture i dont know how to get menu like

[Kukurykus]

Long time ago I added it. If I remeber well you can do by this code: Fly-out menu