Using the same build of Web Viewer on both of our test/production systems. I noticed I was getting different results on our production environment, when looking at updating the Repository Location.
The Prod instance was only showing one one LPAR on a plex, while the test instance was seeing each LPAR of the plex. Clicking on the "DRAS discover" button provided no change. I also noticed that neither system had the elevator slider/thumb scroll on the list box.
The test/production system are exactly the same, except that they point to different systems for the initial logon.
Output Management Web Viewer 12.1
With Chrome and Edge, the repository list dropdown does not invoke the scroll bar on the right side of its window when there are more entries than what fills it at its default size.
When you do that pulldown, you need to use the keyboard down arrow to see past the last entry. The keyboard up and down arrows allow you to get to additional repositories in the list (more than what are initially visible) and after you pause more than a second on an entry it will populate the selected Repository Location and the Alternate Locations for that specific repository.
If you roll your mouse cursor over the Repository Location list box (without clicking therein) and hover there, the tool tip "Select a repository location. If the scrollbars do not appear, use the arrow keys to scroll." will be displayed.