First let me say that I find FNEI really useful! It removes the need for a lot of alt-tabbing out of the game to go look at the wiki. Thanks!
However, I have a suggestion. Currently there is no way to get back to the search dialog quickly. Although the "back" button is a good idea, it only takes you back one step, and if you've been doing a lot of searching around, it may take a lot of steps to get back to the search screen. Maybe you could change the "back" button slightly, so that a left-click takes you back one step (as now), but a right-click takes you straight back to the search dialog? Or, if you prefer, maybe add another button to go straight to the search dialog?
(I've also posted this on forum thread in case no-one spots it here.)