Let me preface this by saying it DOES search entries if you click the search button. But the other WordPress admin screens (Posts, Pages, Comments) all submit the search when you enter text in the search box and hit enter. I would like to request that you make your search work like the other WordPress admin searches in this respect.
Also, you could enhance the text on the button to say "Search Entries" like WordPress has "Search Comments", "Search Pages" and "Search Posts".
I discovered this when showing someone how cool it was that you could search all the entries for one form, and I hit enter, and it didn't find the entry I was looking for. After playing with it a while more, I discovered that using the submit button works as expected.
I only bring these things minor up because everything else is so good already. Thanks again for a great plugin.