[cybmole]

advanced search - "what kind of match to use"- what do you have that set to?

if I search my entire library - with that field dropdown option set to Regular Expresssion:.... and with your find regex, i.e. with this in the title box
.* \((\d{4})\)
it finds only books with a four digit number in the title
8 hits out of nearly 2000 titles.
strangely, none of my 8 hits have brackets around the numbers, so that regex is not quote right yet, but I don't get what you are describing
For me, that code it is finding titles like
The War Within: A Secret White House History 2006-2008
but as per my knowledge of regex, I should find no matches, either the calibre version is a different dialect or the escape-bracket bits are being ignored ?

I also observe the when any advanced search query is loaded into the search bar, a tilde ~ is added to the search term. that's another bit of regex-foo that I don't get