Can't install something provided by a disabled repo from the search results page
When an app/extension is provided by a repo that is disabled, Software handily notifies you that the repo must first be enabled in order for it to be installed. It does this by replacing the "Install" button with the "Install..." button, and clicking it brings up a dialog asking you to enable the repo.
However, this only works while in the details page for an app/extension. It does not work when clicking on the "Install..." button when it's shown in a list of search results. In fact, clicking it appears to have no effect at all.
This happened to me when trying to install the H.264 codec. I tried to watch a .mp4 from Videos, which correctly notified me that I needed to install the H.264 codec, and prompted me to install the codec in Software. It correctly opened a Software window showing all H.264 extensions, but clicking "Install..." for the extension I wanted had no effect until I entered the details page for it. The video below shows it in action.
(Maybe I should also mention that Videos still couldn't play the .mp4 file even after the H.264 codec was installed, but that's a separate issue...)
With that said, this is still an improvement, as it was previously not possible (or at least a pain) to install the H.264 codec from Gnome Software.