Code folding multi-line comments in .c files

I've made "*.mel" files as "C/C++" in File Types in a PyCharm project - MEL is a TCL-based language used in the Maya 3D application that is C-ish enough that I though I could get multiline comment folding, at least.  But I didn't get the folding controls.  So I created a test.c file with something like this in it:

main() {
   /*
    * Multi-line comment syntax
    */

   return 0;
}

The "main() function gets folding controls, but the multi-line comment (in the /* */ pair) has no controls.  Am I missing something - I'd assumed that a multiline comment in C would be a foldable section?