Fix Bug 1580: Force position recalculation after accepting task properties pop-up

FEA: ItEr77S04BugFixing

libreplan-webapp/src/main/java/org/libreplan/web/planner/taskedition/EditTaskController.java

@@ -320,6 +320,8 @@ public class EditTaskController extends GenericForwardComposer {
                 org.zkoss.ganttz.data.Task task = context.getMapper()
                         .findAssociatedBean(taskElement);
                 task.firePropertyChangeForTaskDates();
+
+                context.recalculatePosition(taskElement);
             }
         }
     }