Include directives not appearing in classes unless importing whole namespace into docs

[joldf]

When using the doxygenclass (or doxygenstruct) directive, the #include <...> directive needed for the class is not included in the documentation.

I have turned on breathe_show_include = True (that's the default but I included it explicitly to be safe). I also turned on SHOW_HEADERFILE = YES in the Doxyfile and verified that something roughly right appears to be in the XML files for each class.

More to the point: if I use doxygennamespace for the namespace that encloses any class, then the classes in that namespace do get the include directives in their documentation. Although this isn't ideal either: when a namespace wholly resides in a single header file, I'd like the header to be mentioned right at the top of the namespace, not nested within its members.

Is there anything obvious I'm doing wrong?

(Side note: my preference would be to use a fixed-width font for the #include <...> documentation, rather than just <em> as is currently used - I would also be interested if there's a way to customise that.)