Didier Verna <verna(a)inf.enst.fr&gt; writes: Although your suggestion makes sense as a user-interface improvement, I'm certain that much code depends on case-fold-search doing what it says it does, no matter what the search string is. For example: (let ((case-fold-search nil)) (re-search-for "^Content-Length:") ..) All of these would be broken by your proposed change. Checking whether the function is called interactively would be likely to fail when a higher-level function non-interactively calls a lower-level function to search for a user-specified string. The only good solution I see is to explicitly request this behaviour in higher-level Lisp code. Note that the `with-caps-disable-folding' macro exists for this very purpose. -- Hrvoje, typing this in Paris.