=item B<cutchars:> I<string>
-The characters used as delimiters for double-click word selection. The
-built-in default:
+The characters used as delimiters for double-click word selection.
+
+When the selection extension is in use (the default if compiled in, see
+the @@RXVT_NAME@@perl(3) manpage), a suitable regex using these characters
+will be created (if the resource exists, otherwise, no regex will be
+created). In this mode, characters outside ISO-8859-1 can be used.
+
+When the selection extension is not used, only ISO-8859-1 characters can
+be used. If not specified, the built-in default is used:
B<< BACKSLASH `"'&()*,;<=>?@[]{|} >>