Black flag under GH component

Hello, I want to add a black flag under my Grasshopper component and found out the way to do that is to modify GH_Component.Message from this page. But I’m not sure how to do that. Could anyone help? Thank you.

Black Flag under component (VisualStudio C#) - Grasshopper (

Nevermind, I’ve tried to use this.Message within SolveInstance function and it works.