when Multi-domains is activated, the signup form is messed up

Hi,
when Multi-domains is activated, the signup form is messed up.

Without the plugin, you can see in the picture a normal sign up page, where the domain is displayed after the SIte Name: and before the insert field.

With the plugin activated, you can see in the second picture, the domain has dissapeared after the Site Name: and only a backslash is displayed. The selection item of the domain is siplayed at the bottom of the page.

Can you please fix it?