If you open up an Objective-C file with the ".m" extension, it will set the filetype to Matlab/Octave.
To fix it, you have to go to `Tools=>Configuration Files=>filetype_extensions.conf`. Then remove *.m from `Matlab/Octave=`.
To solve this, you'd have to check the code in the file, which I imagine would be a pain.
However, almost every Objective-C file will contain at least one `#import` or `#include`. You could probably just check if the file contains this.
I'm not sure which is more popular. If Matlab/Octave is more popular, then maybe it should be ahead of Objective-C files.