When signout is initiated from an RP the signout page renders the iframes for sharepoint and the RP tracing it using fiddler the sharepoint cookie is not sent with the wa=wsignout1.0 request and is not destroyed so sharepoint is still logged in. This does
not occur in firefox and chrome.
I have tried switching the iframes for <img> tags and the same behaviour occurs.
If the signout is initiated from sharepoint the rps cookie is sent and destroyed in IE, firefox and chrome.
Any ideas.