Index: openacs-4/packages/chat-portlet/www/chat-portlet.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/chat-portlet/www/chat-portlet.tcl,v
diff -u -N -r1.7 -r1.8
--- openacs-4/packages/chat-portlet/www/chat-portlet.tcl	29 Sep 2013 13:55:54 -0000	1.7
+++ openacs-4/packages/chat-portlet/www/chat-portlet.tcl	7 Aug 2017 23:48:07 -0000	1.8
@@ -49,7 +49,7 @@
 	set can_see_p 0
 	if { $user_p || $admin_p } {
 		set can_see_p 1
-		set num_rooms [expr $num_rooms + 1]
+		set num_rooms [expr {$num_rooms + 1}]
 	}   
     set room_enter_url [export_vars -base "${base_url}room-enter" {room_id {client $default_mode}}]
     set room_html_url [export_vars -base "${base_url}room-enter" {room_id {client html}}]