Hi Sebastian! While making the latest patch (now in CVS), I finally had the time to track gtk_timeout_add, gtk_idle_add and g_io_add_watch inside gtk/gdk/glib sources. The interesting part is that after the related wrappers, they all end using g_source_add; this function uses hook_id (ghook.h) which gets the id from seq_id. :-) In short: seq_id starts from 1 and hook_id is largely used with zero as a non-used/non-active/non-valid value! I updated dillo accordingly and eliminated the uneasy feel of initializing a guint with -1 as an invalid value. Regards Jorge.-