[DiapDealer]

Sigil's PCRE regex engine certainly supports positive lookbehinds. It just doesn't support variable-length lookbehinds--positive or negative. It's a known limitation of the PCRE engine.

Use \K to simulate a variable-length lookbehind:

<p>–( .*?)\K<\/p>

Make sure "Minimal Match" is unchecked when using the above expression.

More on the use of \K here: https://www.regular-expressions.info/keep.html