Use show_all on the notebook and not the window when a new tab is added.

For example, if the roster is hidden in single UI mode and a new chat arrived the roster would unhide.

src/message_window.py

@@ -238,7 +238,7 @@ class MessageWindow(object):
 			self.setup_tab_dnd(control.widget)
 
 		self.redraw_tab(control)
-		self.window.show_all()
+		self.notebook.show_all()
 		# NOTE: we do not call set_control_active(True) since we don't know whether
 		# the tab is the active one.
 		self.show_title()

src/roster_window.py

@@ -1244,7 +1244,7 @@ class RosterWindow:
 		item.set_image(icon)
 		item.connect('activate', self.on_join_gc_activate, account)
 		gc_sub_menu.append(item)
-		
+
 		if len(gajim.connections[account].bookmarks) > 0: # user has at least one bookmark
 			item = gtk.SeparatorMenuItem() # separator
 			gc_sub_menu.append(item)