Thanks for the tip, I will do that and get back to you if I have any issues with it. I appreciate the time and effort.

I opened a default blender settings file in blender 2.79 and imported the model from 2.8. and it worked great with UV unwrap. didn't change anything.

It works flawlessly in 2.79 without me having to do anything or enable any option. I just face this issue in 2.8 beta

Well, I don't have this problem when using 2.7x
Does that mean that this problem will continue with me after the final release?

I sort of found the issue.

Yes, I have. and it shows options for selecting vertices, edges and polygons. but none of that is showing in the UV editor.