CMS Custom field options are not showing up on existing or newly created CMS content

I’m new to Webflow, and I’m currently trying to develop my portfolio on it.
I want to create several posts, e.g., blogs, case studies, UX research, etc. These will be shown on different pages. I’m trying to use this option to categorize the posts.

The problem is that I initially added a few types using “Option Field,” naming it “Project type.”
But now I want to add new options, e.g., “UX Research.” Though It’s added to the custom fields, it is not showing up on CMS. When creating a new CMS post, the “UX Research” option shows. I can not change the 'project type" of the existing projects either.

Link: Webflow - Sarowar's Portfolio

It’s a bit non-obvious due to the 50-shades-of-gray styling, but that’s a scrollbar at the right side. You can drag it or just use your mousewheel to see those lower items.

Ayee! Thank you. I don’t know what it is not that discoverable.