I wrote:
While searching for bugs I found these two Bug 3725: http://bugzilla.lyx.org/show_bug.cgi?id=3725 and bug 3726: http://bugzilla.lyx.org/show_bug.cgi?id=3726but they were both introduced by the patch that implemented the language dialects.
Sorry this was wrong, bug 3725 was "implemented" by Richard and is now fixed and bug 3726 is a bug in the listings-package itself, not in LyX.
regards Uwe
