Milo is correct, but you also have a point. This exchange between you two here is a good example of why the help about the regular expressions needs to be improved.Stefan2 wrote:Milo, you don't have to "guess".
If you enable RegEx, then the regex engine is active for the "replacement scheme",
and so the mentioned help about the regex syntax can be used.
The problem is that the help talks about both regular expression syntax AND the replacement string syntax on the same page in a very ambiguous manner.
The help has one paragraph titled "Escape sequences", and it is not quite clear whether this is about the regex syntax only or about both the regex syntax and the replacement string syntax. After all, the same help talks somewhere in the middle of the page about $1..$32 patterns for the replacement string (which obviously are not element of a regular expression), only to return to regex syntax in the following paragraph. It is rather all mixed up, making it hard for people to understand.
Now, for those among us who are familiar with regular expressions will realize quickly that this or that piece of information only applies to regular expressions but not to the replacement string patterns. But even with this knowledge... Note, how the "Escape sequences" paragraph explains escape sequences like \xNN (character as hex code). Something that would certainly make complete sense in a replacement string too. But does it actually work in a replacement string? According to your comment, it should. But hey, go and try it out... (Hint: No, it doesn't work...

That means, Milo is correct with his assessment. But i don't blame you either, Stefan2, because the documentation is a bit of a mess, and the only way to figure out what is or what is not working is simply to try and see what happens. Not trying to blow a small issue out of proportion, but the documentation could benefit from some loving attention...