From TeX.SX: https://tex.stackexchange.com/q/425883/105447
RefTeX's relations biblatex's multicite commands (such as \parencites, \footcites, \textcites and so on) leave some things to be desired for. Namely, they do not seem to be recognized as citation commands. This results in RefTeX's `reftex-view-crossref` (C-c &) returning "Not on a crossref macro argument". Also, in adding an extra bibkey to an already existing multicite command, it is not possible to access RefTeX's facilities.
Arash Esbati generously provided patches at TeX.SX that go a long way in dealing with these problems. However, support for the presence of global optional arguments (between parentheses) is still missing. At their request, I write to report this issue.
So, I kindly request that this issue be addressed when opportune. With my warmest thanks for the great software, gusbrs _______________________________________________ bug-auctex mailing list firstname.lastname@example.org https://lists.gnu.org/mailman/listinfo/bug-auctex