added back the tooltip explaining username constatrains on the accept invite flow

app/controllers/invitations_controller.rb

@@ -47,7 +47,9 @@ class InvitationsController < Devise::InvitationsController
       flash[:notice] = I18n.t 'registrations.create.success'
       sign_in_and_redirect(:user, user)
     else
-      redirect_to accept_user_invitation_path(:invitation_token => params[:user][:invitation_token]), :error => user.errors.full_messages.join(", ")
+      user.errors.delete(:person)
+      flash[:error] = user.errors.full_messages.join(", ")
+      redirect_to accept_user_invitation_path(:invitation_token => params[:user][:invitation_token])
     end
   end
 

app/views/invitations/edit.html.haml

@@ -1,4 +1,6 @@
 = javascript_include_tag "validation"
+= javascript_tag "Diaspora.Page = 'InvitationsEdit';"
+
 :javascript
   $(function() {
     $("#user_username").focus();
@@ -13,6 +15,8 @@
     = t('.your_account_awaits')
   %h3.accept_invitation_text
     = t('.accept_your_invitation')
+  - flash.each do |name, msg|
+    %p{:class => "login_#{name}"}= msg
 
 .span-10
   %br

public/javascripts/pages/invitations-edit.js

@@ -0,0 +1,7 @@
+Diaspora.Pages.InvitationsEdit = function() {
+  var self = this;
+
+  this.subscribe("page/ready", function(evt, body) {
+    $('#user_username').tipsy({trigger: 'select', gravity: 'w'});
+  });
+};