Hi, I don't understandf the implementation that has been made regarding the need of IDP Proxy :

the IDP proxy feature should cover switch between IDPs, assuming that Service Provider only knows one IDP and does nothing to decide to which one of the IDPs user shoudl be redirect. It's not on th Service Provider side to decide to which IDP user must authenticate (the idp chooser already does that) but on IDP side (on the IDP Proxy...)

regards