Okay, it's a definite tangent to the thread but you've reminded me... what is the use of the Restrict To button?
It is related to Searching, but I cannot figure out how it is relevant / useful. With Hightlight off, the book display is already restrict to matching results. Highlight on, the result would show All books, but only matching results would appear highlighted. Theoretically Highlight off, Restrict To on, you would just get the equivalent of a colored Highlight off book display.
Am I missing something?