overview: new search results can appear at the top of the list, resulting in mis-selections
When performing a search on the Overview, results from search providers are always ordered in the same order they have in the Settings->Search list. For example, Documents search results will always appear above Files results, Software results will appear above Terminal results, and so on.
This means that while performing a search, because results from search providers can become available at any time relative to each other, it's possible for new search results to appear at the top of the list of results, displacing previously-shown ones. The issue with this is that as new results appear, the currently-selected item will be the topmost search result. As a result, if a new search result displaces the current topmost result, pressing Enter will select the new one instead, even though the user never moved to that item themselves. Worse yet, there is no visual feedback for when a search is complete (unless no items are found), so there is no way to know when a new result will appear.
For example, if Documents and Files are both enabled as search providers, it's possible for Files to find & display some results before Documents does. When Documents displays its results, it will place them above Files' results. If the user meant to open a Files result, they will press Enter once Files displays its results. But, if Enter is pressed a second too late, Documents results will appear & become the currently-selected result before the user has time to react, and they will end up opening a Documents result by mistake.
Because of this, the only way to reliably avoid picking the wrong search result by mistake is to enter a search, wait a few seconds until you think the search is finished, and THEN press Enter.
This also affects workflows using a mouse: because search results become displaced, the search result a user wants to click on may move before they have a chance to react to it, leading to a different result being clicked on by mistake.
A solution to this would be to append new search results at the bottom of the list of results as they are found. That way, newly-appearing search results won't displace old ones, so the currently-selected item (via the keyboard) won't be changed as new results appear, and any item under the mouse cursor won't scurry away.
In my opinion, this is much more reliable & expected behaviour than ordering search results by search providers, or even alphabetically.