This has been a pain point of mine since I use D&D beyond a ton to search for things.

If you were to type in the word "fireball" at the top in the search bar D&D beyond will try to help you by giving you closely related results.

However you cannot just click on these results that populate in the dropdown below the search bar and have it start searching. In fact when you click on them (with mouse pointer) all they do is replace your search text in the field above. You still have to press enter again to get it run the search and see the results.

This is the same problem for more advanced users who hit the down arrow to select out of the dropdown (they have to press enter 2x once to populate their search field with the results and second time to run the search query).