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

Then please attach a .blend file to demonstrate the issue, where we can press U unwrap to see the problem.

Just going to the UV Edit workspace in the default startup file seems to work for me.

I sort of found the issue.

The problem occurs when placing a texture in the UV editor. it blocks the visibility of the selection.

When I delete the texture/image placed in the UV editor, the geometry data will appear when I select it in the 3D viewport.

When I place the texture while the geometry is still selected, the geometry remains selected and visible,

but as soon as I deselect. this all goes away. can't see/select the geometry..

File is attached.
The object is already unwraped (it's called: Floor Finish). you can select it. place any image texture. deselect. then you won't be able to select again.

Turns out the issue here is that bpy.context.scene.tool_settings.show_uv_local_view is enabled. However it looks like this setting is not exposed in the ui at all (at least I haven't found it). With this setting only faces that use the currently visible texture will be shown in the uv editor. The actual logic is probably even more obscure.

For now you can just run bpy.context.scene.tool_settings.show_uv_local_view = False in the Python console in Blender and it will work again.

I guess the fix is to show this setting in the ui?

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?

Does the View > UV Local View option work different for you in 2.7x? Did you intend to enable it in this file?

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

This option somehow got enabled in this .blend file, maybe you did it by accident, I don't know.

But it is not enabled by default, and if you would enable it in 2.79 you would get the same result. There are no extra things to do in 2.8 compared to 2.79, just this file has the option enabled for some reason.

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.

I don't know how else to say this: just disable View > UV Local View in the UV Editor in this .blend file, and it will work. This is not enabled by default, only in your .blend file.

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.