diff --git a/ChangeLog b/ChangeLog
index 0b846458b..9e7569438 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -37,6 +37,13 @@
 	-defaultAction]): idem.
 	([UIxAppointmentEditor -viewAction]): idem. 
 
+2008-12-30  Wolfgang Sourdeau  <wsourdeau@inverse.ca>
+
+	* UI/Scheduler/UIxCalListingActions.m ([UIxCalListingActions
+	-eventsBlocksAction]): fixed a crash occuring in the rare
+	situation where an event end date would be inferior than its start
+	date.
+
 2008-12-23  Ludovic Marcotte  <lmarcotte@inverse.ca>
 
 	* SoObjects/Appointments/SOGoAppointmentFolder.{h,m}
diff --git a/SoObjects/Appointments/SOGoCalendarComponent.m b/SoObjects/Appointments/SOGoCalendarComponent.m
index d0d6a3bbc..6f2c2f0b9 100644
--- a/SoObjects/Appointments/SOGoCalendarComponent.m
+++ b/SoObjects/Appointments/SOGoCalendarComponent.m
@@ -431,7 +431,7 @@ _occurenceHasID (iCalRepeatableEntityObject *occurence, NSString *recID)
 	  [currentComponent removeAllExceptionDates];
 	  for (count = 0; count < max; count++)
 	    [currentComponent addToExceptionDates: [newDates objectAtIndex: count]];
-	}      
+	}
     }
 }
 
diff --git a/UI/Scheduler/UIxCalListingActions.m b/UI/Scheduler/UIxCalListingActions.m
index a0751c4f5..3ef5c0eea 100644
--- a/UI/Scheduler/UIxCalListingActions.m
+++ b/UI/Scheduler/UIxCalListingActions.m
@@ -371,8 +371,14 @@ static inline void
 _feedBlockWithDayBasedData(NSMutableDictionary *block, unsigned int start,
 			   unsigned int end, unsigned int dayStart)
 {
-  unsigned int delta, quarterStart, length;
-
+  unsigned int delta, quarterStart, length, swap;
+  
+  if (start > end)
+    {
+      swap = end;
+      end = start;
+      start = swap;
+    }
   quarterStart = (start - dayStart) / quarterLength;
   delta = end - dayStart;
   if ((delta % quarterLength))