Local Variable "mode" ignored ?

Hello,

I have some .h files which contain c++ headers. I know, they should be 
called .hh or something like that, but I can't change this.
What worked a long time for me was this footer in each of the .h files:

}; // END class someclass


# endif
// Local Variables:
// mode: c++
// End:
// EOF

Today I recognized that the .h files are no longer in c++ mode, but in c 
mode. I don't know when this happened, can be quite a while ago. What have 
I screwed up ???

Thanks !

Markus Grunwald