Display errors on login form
Since 2.0, we have a behavior change on how errors are displayed. For example when you enter the wrong password, we use the error template and we don't see anymore the login form. The side effect is that we loose the initial context, as the "go to portal" button is using the cancel parameter to clean pdata. This parameter is mandatory in some cases, so we can't remove it.
We should have the possibility to display some errors on the login form, or on the password form.