apple tv app not showing thumbnails

Firstly, I've recently learned that "Apple TV" is an app for Windows that seems to do all or most of the same things as iTunes.

Except for Apple Home Sharing (home streaming) from a local computer to an Apple TV box (or to another computer, or iPhone, or iPad). Last time I checked, that wasn’t an option in the new Apple TV app for Windows.

All this time I thought it was the name of that little black box that connects to my projector and plays my iTunes library media.

And you were right. Despite the differences, Apple chose to use the same name for both. A tad confusing for sure.

Does this mean I no longer need iTunes on my PC?

Use one or the other. Using both interchangeably has been blocked, unfortunately, due to changes in shared support files.

Can I uninstall it without losing my media?

The local iTunes library will be sort-of taken over by the new Apple TV app. After that is done, you should be able to uninstall iTunes for Windows.

I can't see thumbnails

Probably some local caches for the app may need to be purged, so that they can be fetched again freshly, but I’m not confident on how to go about that manually on Windows.

A second, comparatively minor problem: My mouse's scroll wheel doesn't work in this app. Neither does the down arrow key. How can I easily scroll through a long list of shows?

That’s a first that I have heard of this issue. If a computer cold restart doesn’t fix it, then consider contacting an expert from the Apple Support staff. Contact Apple for support and service (phone numbers) or start your support request online (chat/​email/​callback).