Possible bug in Aquamacs?

[Robert P. Goldman]

I was editing a texinfo file, and then wanted to use the "Command" >
"Makeinfo HTML" menu item.

This prompted me to choose a master file (I believe this is an
Auctex-style thing, which you use to find all the files in a multi-file
document, but this does not seem to happen in AuCTeX).

Aquamacs prompts me for this master file with a file selector box, with
the current file as the default.

But if I try to select this filename, the menu prompts me with a warning
that it will replace the file.

Is this an incorrect attempt on the part of Aquamacs to use Mac OS X
widgets to implement an emacs filename query?

I wanted to track this down, but when I try to use ^H-C to figure out
what function is being called, it gets intercepted somehow and all I
learn is that it's "menu-function-111". This is not something that M-x
find-function knows how to track down for me. If you can point me at a
way to drill through this opaque intermediary, I'll track this down
further myself before bothering anyone again.

thanks,
r