Whitelisting a username containing spaces

Correct … the plugin is splitting the whitelist using the comma or any space character. Right now there’s no way to escape this using a backslash or something like a URL encoding, like you tried.

After testing, I just pushed an update to the plugin that allows space characters in the whitelist. I didn’t bump the version number (yet) so you will have to delete and reinstall the plugin. Please test it out and let me know if it works for you.

(Originally when I made the plugin I made it very restrictive with respect to allowed characters to have paranoid protection against XSS, CSRF and SQL injection attacks. It’s still more restrictive than WordPress but should now allow space characters.)

Thanks for the report!