login: only try to login when not yet logged in; always set camefrom in request

cco/member/auth.pt

@@ -6,6 +6,7 @@
              tal:define="principal request/principal/id;
                    baseUrl python:request.URL[-1];
 	   			   camefrom python:request.get('camefrom') or baseUrl;
+                   dummy python:request.form.setdefault('camefrom', baseUrl);
 				   dummy item/checkAuth">
     <p style="color: Red"
        tal:condition="request/error_message|nothing"

cco/member/browser.py

@@ -62,12 +62,12 @@ def validateToken(token, secret=None):
 class LoginBase:
 
     def __call__(self):
-        if self.authMethod == 'oidc':
+        if self.isAnonymous and self.authMethod == 'oidc':
             return self.authOidc()
         return super(LoginBase, self).__call__()
 
     def checkAuth(self):
-        if self.authMethod == 'oidc':
+        if self.isAnonymous and self.authMethod == 'oidc':
             return self.authOidc()
 
     @Lazy