[Plugin: Register Plus Redux] Conflicts with Sexybookmark

I was trying to force new users to use their emails as usernames by setting the plugin “Register Plus Redux” but I found the username box still appeared on the registration page…..

I tried to turn off my plugins one by one and have found it was Sexybookmark conflicting with it….

I couldn’t see why…….now I’m trying to look for the solution…
Is there anyway to manually add the code to force the new users use their email as usernames?

any other suggestions will also be welcome!!