What r the most common reasons for not being able to edit UVs?

In 2.80

I have unwrapped the UVs. But I can’t edit them now.
I tested this with another object in a different file and that was not a problem, so I guess it’s something specific to my other file.
Also, the UVs only show while I have them all selected in the 3D view. Is there a way to have them all showing whether they’re selected or not?

Thanks

For the visibility - you have to toggle sync selection in viewport with uv view. And what is happening when you try to edit uvs?

I move the mouse over to the UV Editor window, and press any of the modifying shortcuts (s, g, r) but nothing happens. The UVs remain selected but show no change.

And where EXACTLY is the “sync selection”. All I know is that it’s in the viewport. I wish there was only one place in the viewport.

Only moving mouse to uv window will not select which verticles you want to move, you have to click and select them.

Sorry, I forgot to mention that after hovering the mouse on the UV editor window I hit A (select all).

Strangely, the solution was to remove the texture I had on that mesh.

UV maps are independent of textures AFAIK. You could open any other texture and UV would be intact.
The only thing that comes to mind is that you’ve pinned verticles (they are pink then?). That locks part of UV from modification.