Hi Eli and Alan,

Thanks for investigating.

Don't know if this is of much help, but here's a simpler test file 
(BitmapFontFace4.h).

If I delete all the "YBitmapZ" lines so that only the full-word 
occurrences of "Bitmap" are left in the file, then C-u M-% replaces 
everything but replace-regexp doesn't still.

Daniel