src/Pure/Tools/debugger.scala

--- a/src/Pure/Tools/debugger.scala	Tue Nov 03 11:24:42 2015 +0100
+++ b/src/Pure/Tools/debugger.scala	Tue Nov 03 13:54:34 2015 +0100
@@ -114,7 +114,7 @@
   case object Update
 
   private val delay_update =
-    Simple_Thread.delay_first(global_state.value.session.output_delay) {
+    Standard_Thread.delay_first(global_state.value.session.output_delay) {
       global_state.value.session.debugger_updates.post(Update)
     }