how can i add menu on my custom expression contorls?

[한량입니다]

title.

like this, i wonder how did they make two chehckbox options on one effect

[Rick Gerard]

More than one checkbox control in a single effect must be created with a script, extension, or plugin.  You can't create anything in the Effects Control Panel with an expression. You can only control what is placed there. 

Nothing is keeping you from adding more than one expression control Check Box.

[한량입니다]

Thank you for answer, I see.

Then how can they do that and why I can use that custom effect?

What can I search for find that way?

[OussK · Accepted solution]

I think you ask for the pseudo effects, check this plugin that allows you to do that https://aescripts.com/pseudo-effect-maker/ 

[한량입니다]

yes it is!
Thx for answer 🙂