diff --git a/navalplanner-business/src/main/java/org/navalplanner/business/planner/entities/AggregateOfResourceAllocations.java b/navalplanner-business/src/main/java/org/navalplanner/business/planner/entities/AggregateOfResourceAllocations.java
index 1c6d51a8d..5f3425d53 100644
--- a/navalplanner-business/src/main/java/org/navalplanner/business/planner/entities/AggregateOfResourceAllocations.java
+++ b/navalplanner-business/src/main/java/org/navalplanner/business/planner/entities/AggregateOfResourceAllocations.java
@@ -81,4 +81,32 @@ public class AggregateOfResourceAllocations {
         return sum;
     }
 
+    public LocalDate getStart() {
+        if(isEmpty()){
+            throw new IllegalStateException("the aggregate is empty");
+        }
+        return getAllocationsSortedByStartDate().get(0).getStartDate();
+    }
+
+    public LocalDate getEnd(){
+        if(isEmpty()){
+            throw new IllegalStateException("the aggregate is empty");
+        }
+        LocalDate result = null;
+        for (ResourceAllocation<?> allocation : resourceAllocations) {
+            result = bigger(allocation.getEndDate(), result);
+        }
+        return result;
+    }
+
+    private LocalDate bigger(LocalDate one, LocalDate other) {
+        if (one == null) {
+            return other;
+        }
+        if (other == null) {
+            return one;
+        }
+        return one.compareTo(other) > 0 ? one : other;
+    }
+
 }
diff --git a/navalplanner-business/src/main/java/org/navalplanner/business/planner/entities/Task.java b/navalplanner-business/src/main/java/org/navalplanner/business/planner/entities/Task.java
index d20ecdb1c..7246798c7 100644
--- a/navalplanner-business/src/main/java/org/navalplanner/business/planner/entities/Task.java
+++ b/navalplanner-business/src/main/java/org/navalplanner/business/planner/entities/Task.java
@@ -30,6 +30,7 @@ import org.apache.commons.lang.Validate;
 import org.hibernate.validator.NotNull;
 import org.joda.time.DateTime;
 import org.joda.time.Days;
+import org.joda.time.LocalDate;
 import org.navalplanner.business.orders.entities.HoursGroup;
 import org.navalplanner.business.resources.entities.Criterion;
 import org.navalplanner.business.resources.entities.Resource;
@@ -246,10 +247,14 @@ public class Task extends TaskElement {
     }
 
     public void mergeAllocation(CalculatedValue calculatedValue,
-            Integer daysDuration, List<ResourceAllocation<?>> newAllocations,
+            AggregateOfResourceAllocations aggregate,
+            List<ResourceAllocation<?>> newAllocations,
             List<ModifiedAllocation> modifications) {
         this.calculatedValue = calculatedValue;
-        setDaysDuration(daysDuration);
+        final LocalDate start = aggregate.getStart();
+        final LocalDate end = aggregate.getEnd();
+        setStartDate(start.toDateTimeAtStartOfDay().toDate());
+        setDaysDuration(Days.daysBetween(start, end).getDays());
         addAllocations(newAllocations);
         for (ModifiedAllocation pair : modifications) {
             Validate.isTrue(resourceAllocations.contains(pair.getOriginal()));
diff --git a/navalplanner-webapp/src/main/java/org/navalplanner/web/planner/allocation/AllocationResult.java b/navalplanner-webapp/src/main/java/org/navalplanner/web/planner/allocation/AllocationResult.java
index 7069cad4b..08d6f46e1 100644
--- a/navalplanner-webapp/src/main/java/org/navalplanner/web/planner/allocation/AllocationResult.java
+++ b/navalplanner-webapp/src/main/java/org/navalplanner/web/planner/allocation/AllocationResult.java
@@ -62,8 +62,6 @@ public class AllocationResult {
 
     private final CalculatedValue calculatedValue;
 
-    private List<ResourceAllocation<?>> allSortedByStartDate;
-
     private final Task task;
 
     AllocationResult(
@@ -119,16 +117,12 @@ public class AllocationResult {
     }
 
     public void applyTo(Task task) {
-        task.mergeAllocation(getCalculatedValue(), getDaysDuration(), getNew(),
+        task.mergeAllocation(getCalculatedValue(), aggregate, getNew(),
                 getModified());
     }
 
     public List<ResourceAllocation<?>> getAllSortedByStartDate() {
-        if (allSortedByStartDate != null) {
-            return allSortedByStartDate;
-        }
-        return allSortedByStartDate = aggregate
-                .getAllocationsSortedByStartDate();
+        return aggregate.getAllocationsSortedByStartDate();
     }
 
     public Task getTask() {
diff --git a/navalplanner-webapp/src/main/java/org/navalplanner/web/planner/allocation/ResourceAllocationModel.java b/navalplanner-webapp/src/main/java/org/navalplanner/web/planner/allocation/ResourceAllocationModel.java
index e529bfe9c..0d32630d7 100644
--- a/navalplanner-webapp/src/main/java/org/navalplanner/web/planner/allocation/ResourceAllocationModel.java
+++ b/navalplanner-webapp/src/main/java/org/navalplanner/web/planner/allocation/ResourceAllocationModel.java
@@ -20,6 +20,7 @@
 
 package org.navalplanner.web.planner.allocation;
 
+import java.util.Date;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Set;
@@ -130,7 +131,13 @@ public class ResourceAllocationModel implements IResourceAllocationModel {
 
     private void doTheAllocation(AllocationResult allocationResult) {
         allocationResult.applyTo(task);
-        ganttTask.setEndDate(task.getEndDate());
+        ganttTask.setBeginDate(toDate(allocationResult.getAggregate()
+                .getStart()));
+        ganttTask.setEndDate(toDate(allocationResult.getAggregate().getEnd()));
+    }
+
+    private Date toDate(LocalDate start) {
+        return start.toDateTimeAtStartOfDay().toDate();
     }
 
     private List<Resource> getResourcesMatchingCriterions() {