How to allow spaces in usernames?

[Kirill N]

It seems that it's currently not possible to have a space in a username on my site. I checked the "Allowed characters in display names" setting and it's set to "a-zA-Z0-9", but if I add a space there it doesn't work. Any ideas?

 

Thanks

[sunrisecc]

I put a blank between the Z and 0.

One can also add ' ' at the end. (blank space between the quotes)