diff --git a/src/backend/scheduler.cc b/src/backend/scheduler.cc
index 052a757..070510d 100644
--- a/src/backend/scheduler.cc
+++ b/src/backend/scheduler.cc
@@ -281,6 +281,9 @@ class Extender
       }
     }
   }
+/*
+
+	// the following methods are never used in step forward (by now)
 
   /// \brief Manages a single Thread object, depending on its state.
   ///
@@ -299,7 +302,7 @@ class Extender
     front = t.get_elapsed_time();
     switch (walk)
     {
-/*
+
     /// If the thread is RUNNING, its requests are updated in cascade,
     /// the counters are decreased, and the state is updated depending
     /// on the remaining time and the remaining quantum.
@@ -361,7 +364,7 @@ class Extender
         }
         break;
       }
-*/
+
     /// If the thread is the first on the ready_queue, try to run. The
     /// thread may block on a request.
     case walk_to_allocate_cpu:
@@ -393,10 +396,11 @@ class Extender
         }
         break;
       }
+
     }
     front = old_front;
   }
-
+*/
 
 
 
@@ -507,7 +511,9 @@ Scheduler::step_forward(History& history, CPUPolicy& cpu_policy) throw(UserInter
 	// FIXME: handle me! I'm not just a pretty boolean, I want to be *USED*! *EXPLOITED*!
 	//        *RAPED*! *MAKE ME BLEED*!
 	bool simulation_ended = true; // Assume we've finished. Then prove me wrong.
-	unsigned int current_instant = history.get_size(); /* They should be equivalent */
+	// since history always contains at leas one element..
+	assert (history.get_size() > 0);
+	unsigned int current_instant = history.get_size() - 1; /* They should be equivalent */
 
 	ConcreteHistory& concrete_history = (ConcreteHistory&) history;
  
@@ -528,8 +534,12 @@ Scheduler::step_forward(History& history, CPUPolicy& cpu_policy) throw(UserInter
 			// 1. mark future threads as ready, if appropriate
 			if(current.get_state() == Schedulable::state_future)
 				{
+					// if there is at least a future process, don't terminate the simulation
 					Process& parent = current.get_process();
-					if(parent.get_elapsed_time() == current.get_arrival_time())
+					if (parent.get_state() == Schedulable::state_future)
+						simulation_ended = false;
+					// start a thread only if its parent is arrived!
+					if(parent.get_arrival_time() <= current_instant && parent.get_elapsed_time() == current.get_arrival_time())
 					{
 						current.set_state(Schedulable::state_ready);
 						// in this way we will never have threads ready having remaining time == 0
@@ -537,7 +547,7 @@ Scheduler::step_forward(History& history, CPUPolicy& cpu_policy) throw(UserInter
 							current.set_state(Schedulable::state_terminated);
 					}
 				}
-           
+
 			// Save the current running thread for future usage, if it hasn't ended
 			// its allotted time
 			if(current.get_state() == Schedulable::state_running)
@@ -706,7 +716,11 @@ Scheduler::step_forward(History& history, CPUPolicy& cpu_policy) throw(UserInter
 
 
 
-
+		// FIXME
+		//                      FIXME
+		// FIXME
+		// the following condition is not sufficient. we must also
+		// be sure that no other processes are ready.
 		if (!found)
 			simulation_ended = true;
 					
diff --git a/src/testsuite/scheduling-wizards/wizard-gap-fail b/src/testsuite/scheduling-wizards/wizard-gap-fail
new file mode 100644
index 0000000..fee7748
--- /dev/null
+++ b/src/testsuite/scheduling-wizards/wizard-gap-fail
@@ -0,0 +1,72 @@
+set cpu-policy 3 
+add resource
+
+add resource
+forchetta
+false
+1
+0
+
+add process
+Pitagorici
+0
+0
+
+add thread 1
+Pitagora
+4
+0
+0
+
+add request 1 1
+0
+
+add subrequest 1 1 1
+0
+4
+add subrequest 1 1 1
+0
+4
+
+
+add request 1 1
+2
+
+add subrequest 1 1 2
+0
+4
+
+
+add process
+Scuola di Mileto
+3
+0
+
+add thread 2
+Anassimene
+6
+0
+0
+
+add thread 2
+Anassimandro
+2
+0
+0
+
+
+add request 2 1
+0
+add subrequest 2 1 1
+0
+2
+
+add request 2 2
+0
+add subrequest 2 2 1
+0
+2
+
+
+
+run