I am not sure, whether this is alread fixed in a newer version, but since I just spend hours trying to figure it out, I wanted to let you know.
With version 2014.1.320 the non-breaking space character (nbsp, ASCII 0xA0 or 160) is parsed as a whitespace when the editor is opened. But when the editor is closed, this is parsed as an invalid token, corrupting the parsed compilation unit. The reason seems to be, that if the file is opened in the editor, the parser gets a normalized string, where non-breaking spaces are replaced with regular spaces. If its not, it gets the text as it is found in the text file.
Since the compiler doesn't show any errors, non-breaking spaces seem to be valid characters.
If the problem is still in the latest release, please also make sure this works in the WPF version too.
Best regards, Tobias Lingemann.