diff --git a/src/core.py b/src/core.py
index 3fcfabfb..199bf237 100644
--- a/src/core.py
+++ b/src/core.py
@@ -1213,12 +1213,11 @@ class Core(object):
         Move the new-messages separator at the bottom on the current
         text.
         """
-        try:
-            room = self.current_tab().get_room()
-        except:
+        window = self.current_tab().get_text_window()
+        if not window:
             return
-        room.remove_line_separator()
-        room.add_line_separator()
+        window.remove_line_separator()
+        window.add_line_separator()
         self.refresh_window()
 
     def information(self, msg, typ=''):
diff --git a/src/tabs.py b/src/tabs.py
index 5f851cc6..bb9db89e 100644
--- a/src/tabs.py
+++ b/src/tabs.py
@@ -124,6 +124,12 @@ class Tab(object):
         """
         raise NotImplementedError
 
+    def get_text_window(self):
+        """
+        Returns the principal TextWin window, if there's one
+        """
+        return None
+
     def on_input(self, key):
         pass
 
@@ -348,6 +354,7 @@ class MucTab(ChatTab):
         for user in sorted(users, key=compare_users, reverse=True):
             user.color = theme.LIST_COLOR_NICKNAMES[i % nb_color]
             i+= 1
+        self.text_win.rebuild_everything(self.get_room())
         self.core.refresh_window()
 
     def command_nick(self, arg):
@@ -540,6 +547,9 @@ class MucTab(ChatTab):
     def get_name(self):
         return self._room.name
 
+    def get_text_window(self):
+        return self.text_win
+
     def get_room(self):
         return self._room
 
@@ -664,6 +674,9 @@ class PrivateTab(ChatTab):
     def get_room(self):
         return self._room
 
+    def get_text_window(self):
+        return self.text_win
+
     def just_before_refresh(self):
         return
 
@@ -939,6 +952,9 @@ class ConversationTab(ChatTab):
     def get_room(self):
         return self._room
 
+    def get_text_window(self):
+        return self.text_win
+
     def just_before_refresh(self):
         return