Index: indico/MaKaC/webinterface/rh/conferenceModif.py
===================================================================
--- indico/MaKaC/webinterface/rh/conferenceModif.py	(revision a89f947d56a37649ac31f3d9ef2c3684dbf4098a)
+++ indico/MaKaC/webinterface/rh/conferenceModif.py	(revision 0951a821de1f0ce1612da200292d835cf8c7502a)
@@ -72,5 +72,4 @@
 from MaKaC.webinterface.mail import GenericMailer
 from MaKaC.webinterface.mail import GenericNotification
-from MaKaC.webinterface.wcomponents import WErrorMessage
 from MaKaC.common import pendingQueues
 from MaKaC.common import mail
@@ -2120,5 +2119,6 @@
     def _checkParams( self, params ):
         RHConferenceModifBase._checkParams( self, params )
-        self._errorMsg = params.get("errorMsg","")
+        self._errorMsg = ""
+        self._infoMsg = ""
 
     def _process( self ):
@@ -2128,5 +2128,5 @@
         else:
             p = conferences.WPConfModifParticipants( self, self._target )
-            return p.display(errorMsg=self._errorMsg)
+            return p.display(errorMsg=self._errorMsg, infoMsg=self._infoMsg)
 
 
@@ -2188,5 +2188,5 @@
 
 
-class RHConfModifParticipantsAction(RHConferenceModifBase):
+class RHConfModifParticipantsAction(RHConfModifParticipants):
     _uh = urlHandlers.UHConfModifParticipantsAction
 
@@ -2286,8 +2286,8 @@
                         GenericMailer.sendAndLog(GenericNotification(data),self._conf,"participants",self._getUser())
                         infoList.append( _("The message has been send to  %s %s.")%(participant.getFirstName(), participant.getFamilyName()))
-        url = RHConfModifParticipants._uh.getURL(self._conf)
-        url.addParam("errorMsg",errorList)
-        url.addParam("infoMsg",infoList)
-        self._redirect(url)
+        if errorList:
+            self._infoMsg = infoList
+            self._errorMsg = errorList
+        return RHConfModifParticipants._process(self)
 
 
@@ -2312,5 +2312,5 @@
 
 
-class RHConfModifParticipantsAddSelected(RHConferenceModifBase):
+class RHConfModifParticipantsAddSelected(RHConfModifParticipants):
     _uh = urlHandlers.UHConfModifParticipantsAddSelected
 
@@ -2358,7 +2358,7 @@
                         is already in the participants' list""")%participant.getEmail())
 
-        url = RHConfModifParticipants._uh.getURL(self._conf)
-        url.addParam("errorMsg", errorList)
-        self._redirect(url)
+        if errorList:
+            self._errorMsg = errorList
+        return RHConfModifParticipants._process(self)
 
 
@@ -2373,5 +2373,5 @@
 
 
-class RHConfModifParticipantsAddNew(RHConferenceModifBase):
+class RHConfModifParticipantsAddNew(RHConfModifParticipants):
     _uh = urlHandlers.UHConfModifParticipantsAddNew
 
@@ -2405,7 +2405,7 @@
                         is already in the participants' list""")%participant.getEmail())
 
-        url = RHConfModifParticipants._uh.getURL(self._conf)
-        url.addParam("errorMsg", errorList)
-        self._redirect(url)
+        if errorList:
+            self._errorMsg = errorList
+        return RHConfModifParticipants._process(self)
 
 
@@ -2421,9 +2421,8 @@
 
 
-class RHConfModifParticipantsInviteSelected(RHConferenceModifBase):
+class RHConfModifParticipantsInviteSelected(RHConfModifParticipants):
     _uh = urlHandlers.UHConfModifParticipantsInviteSelected
 
     def _process( self ):
-        params = {}
         errorList = []
         eventManager = self._getUser()
@@ -2465,8 +2464,7 @@
                         is already in the participants' list""")%participant.getEmail())
 
-        url = RHConfModifParticipants._uh.getURL(self._conf)
-        url.addParam("errorMsg", errorList)
-        self._redirect(url)
-
+        if errorList:
+            self._errorMsg = errorList
+        return RHConfModifParticipants._process(self)
 
 class RHConfModifParticipantsNewToInvite(RHConferenceModifBase):
@@ -2480,5 +2478,5 @@
 
 
-class RHConfModifParticipantsInviteNew(RHConferenceModifBase):
+class RHConfModifParticipantsInviteNew(RHConfModifParticipants):
     _uh = urlHandlers.UHConfModifParticipantsInviteNew
 
@@ -2502,7 +2500,7 @@
                         is already in the participants' list""")%participant.getEmail())
 
-        url = RHConfModifParticipants._uh.getURL(self._conf)
-        url.addParam("errorMsg", errorList)
-        self._redirect(url)
+        if errorList:
+            self._errorMsg = errorList
+        return RHConfModifParticipants._process(self)