Currently, when opening .pyx files, by default they get shown as plain text rather than cython (a module to make python extensions with C-like syntax and interface with C/C++/Fortran code). It’s possible to switch to python syntax manually, but then they don’t get the colors right as cython has many additional keywords (e.g. ‘double’, ‘cdef’, ‘cpdef’, etc.) which are not recognized by sublime.
Would be nice if sublime could color them in a similar way as when generating an annotated .html version of the code from cython (in the compiling options).