suggestion on moving the check button

I modified the _form_alter function for this module to move the button inside the standard user.module username and email collection fieldset as it makes sense to show the test button as close as possible to the username field. Otherwise you have no real control over where the check button will appear and with a registration form with many other elements the link between the function of the button and field it acts on could be lost.

so, in function username_check_path_form I modified the $form settings from $form['username_button'] to $form['account']['username_button'].