-let increase_font_size () = incr current_font_size
-let decrease_font_size () = decr current_font_size
-let reset_font_size () = current_font_size := default_font_size ()
+let increase_font_size () =
+ incr current_font_size; observe ()
+let decrease_font_size () =
+ decr current_font_size; observe ()
+let reset_font_size () =
+ current_font_size := default_font_size (); observe ()