Blocking editor > syntax highlighting menu

Seems like something in the source is blocking the `Editor` > `Syntax Highlighting` submenu. Whenever opening a project containing a `mapcss` file, the **Syntax Highlighting** submenu becomes _void_. I have compared it with [squirrel-xcode-coloring](https://github.com/Skippern/squirrel-xcode-coloring), but that one seems to work fine.
