• Going to Central Admin-> Operations ->Alternate Access Mappings and updating my default zone url to my new url
• Using the IIS management console to change the host header of my site collection's web application to my new url

• The authentication cookie had it's path set to /MembersArea  (note the case)
• The back office web page i was trying to load in the iframe was http://foo-backoffice/membersarea/updates/layout1.asp

I was building a breadcrumb trail for a site I was working on, and using the SiteMapPath control to render the breadcrumb. I wanted to hide the root node from the breadcrumb, but as the SiteMapControl gets its data directly from a SiteMapProvider rather than via a SiteMapDataSource, we cant use the SiteMapDataSource.ShowStartingNode property to hide the root node. I used this workaround:

Handle the SiteMapPath's ItemCreated event, where you can hide the root node:

    //override the Page's OnInit
    protected override void OnInit(EventArgs e)
    {
        base.OnInit(e);

        Breadcrumb.ItemCreated += new SiteMapNodeItemEventHandler(Breadcrumb_ItemCreated);
    }

    void Breadcrumb_ItemCreated(object sender, SiteMapNodeItemEventArgs e)
    {

        //hide the root node, and it's following path separator
        if (e.Item.ItemIndex == 0 
            | (e.Item.ItemIndex ==1 && e.Item.ItemType ==SiteMapNodeItemType.PathSeparator))
        {
            e.Item.Visible = false;
        }
    }

• Make sure the 'Membership Provider Name' and 'Role Manager Name' match the values you have specified in your site's web.config AND Central Administration's web.config.
  

• If your providers access a backing store, make sure its is accessible. For example, if you are using the AspNetSqlMembershipProvider and your connection string is set to use integrated security, the identity of your application pool(s) will need access to the ASPNET SQL database.
  

• Connect to your server using Remote Desktop
• Open Terminal Services Manager
• Locate the session you wish to connect to, and either double-click, or choose 'connect' from the context menu
• Your session should magically switch to the one you selected
  

MediaElement me1= XamlReader.Load(@"<MediaElement 


                                xmlns='http://schemas.microsoft.com/winfx/2006/xaml/presentation' 


                                Name='me1'
Opacity='0' />") as MediaElement;

LayoutRoot.Children.Add(mediaElement);

VideoBrush vb = new VideoBrush();

vb.SourceName = me1.Name;

MyRectangle.Fill=vb; 

That code works fine in beta 1, but in beta 2 MyRectangle remains blank!

The clue to fixing this is included in the breaking changes doc:

"XamlReader.Load(string) has been changed to always create an implicit namescope."

MediaElement me1 = XamlReader.Load(@"<MediaElement

                                 xmlns='http://schemas.microsoft.com/winfx/2006/xaml/presentation'

                                 Name='me1'
AutoPlay='False' Opacity='0.0' IsHitTestVisible='False' >

                                    <MediaElement.Resources>

                                       <VideoBrush
Name='vb1' SourceName='me1'/>

                                    </MediaElement.Resources>

                                    </MediaElement>")
as MediaElement;

VideoBrush vb = me1.FindName("vb1") as VideoBrush;

MyRectangle.Fill=vb;