Is it possible to search expression A AND expression B in a proximity range? What I mean is, for example, "text A" AND "text B" in the same paragraph or in a proximity range (for example: 80 characters).
Best regards.

Well I think these suggestions come close to what you want to achive:

Using Perl regexp this searches for "text A" and "text B" in the same paragraph:

text A[^\r\n]+text B
([^\r\n]+ equals everything but CR and LF which separates paragraphs).

Proximity could look something like:

text A.{1,80}text B
(.{1,80} = any chars from 1 to 80 occurence (greedy)).

(And remember to check "regular expressions" in the find dialog and activate Perl Regexp in the configuration)

Thank you very much! Definitively I have to study the Perl search syntax. It's really powerful.

Very good solution. However, the "proximity" example has one problem: It will not match if the two occurences are separated by a CR/LF. As far as I know, there is no way to tell UE'S Perl regex engine to allow the dot (.) to also match newlines.

A possible workaround could be used if there is one character that you know for certain will not turn up in your files, e.g. ÿ (ASCII 255). If that's the case, you can rework the regex to
(If you also want to allow for the possibility that there are zero characters between the two texts ("textAtextB") then use * instead of + in the first regex and {0,80} instead of {1,80} in the second regex)

HTH,
Tim

P.S. If anyone can think of a more elegant solution, I'd be glad to hear about it. I wonder if it's really necessary to use such an ugly trick. Maybe it would be a sensible feature request to add the option "dot matches newline"...

It's not an ugly trick and it works perfectly!