diff --git a/navalplanner-business/src/main/java/org/navalplanner/business/common/Flagged.java b/navalplanner-business/src/main/java/org/navalplanner/business/common/Flagged.java
new file mode 100644
index 000000000..91c5c2d5a
--- /dev/null
+++ b/navalplanner-business/src/main/java/org/navalplanner/business/common/Flagged.java
@@ -0,0 +1,92 @@
+/*
+ * This file is part of NavalPlan
+ *
+ * Copyright (C) 2011 Igalia, S.L.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package org.navalplanner.business.common;
+
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.Set;
+
+/**
+ * Wraps a value with several arbitrary flags.
+ *
+ * @author Oscar Gonzalez Fernandez <ogonzalez@igalia.com>
+ *
+ * @param <T>
+ *            the value that can have flags associated with it
+ * @param <F>
+ *            the type of the flags
+ */
+public class Flagged<T, F> {
+
+    public static <T, F> Flagged<T, F> justValue(T value) {
+        return new Flagged<T, F>(value, new HashSet<F>());
+    }
+
+    public static <T, F> Flagged<T, F> withFlags(T value, F... flags) {
+        return new Flagged<T, F>(value, new HashSet<F>(Arrays.asList(flags)));
+    }
+
+    private final T value;
+
+    private final Set<F> flags;
+
+    private Flagged(T value, Set<F> flags) {
+        this.value = value;
+        this.flags = Collections.unmodifiableSet(flags);
+    }
+
+    public Flagged<T, F> withFlag(F flag) {
+        Set<F> newFlags = new HashSet<F>(flags);
+        newFlags.add(flag);
+        return new Flagged<T, F>(value, newFlags);
+    }
+
+    public Flagged<T, F> withoutFlag(F flag) {
+        Set<F> newFlags = new HashSet<F>(flags);
+        newFlags.remove(flag);
+        return new Flagged<T, F>(value, newFlags);
+    }
+
+    public T getValue() {
+        return value;
+    }
+
+    public boolean isFlagged() {
+        return !this.flags.isEmpty();
+    }
+
+    public Set<? extends F> getFlags() {
+        return this.flags;
+    }
+
+    public boolean isFlaggedWith(F flag){
+        return this.flags.contains(flag);
+    }
+
+    public boolean isFlaggedWithSomeOf(F... flags) {
+        for (F each : flags) {
+            if (this.isFlaggedWith(each)) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+}
diff --git a/navalplanner-business/src/main/java/org/navalplanner/business/planner/entities/allocationalgorithms/AllocationModification.java b/navalplanner-business/src/main/java/org/navalplanner/business/planner/entities/allocationalgorithms/AllocationModification.java
index f79dbaec3..20c7aa2ff 100644
--- a/navalplanner-business/src/main/java/org/navalplanner/business/planner/entities/allocationalgorithms/AllocationModification.java
+++ b/navalplanner-business/src/main/java/org/navalplanner/business/planner/entities/allocationalgorithms/AllocationModification.java
@@ -34,6 +34,16 @@ import org.navalplanner.business.resources.entities.Resource;
  */
 public abstract class AllocationModification {
 
+    public static boolean allFullfiled(
+            Collection<? extends AllocationModification> modificationsDone) {
+        for (AllocationModification each : modificationsDone) {
+            if (!each.satisfiesModificationRequested()) {
+                return false;
+            }
+        }
+        return true;
+    }
+
     public static List<ResourceAllocation<?>> getBeingModified(
             Collection<? extends AllocationModification> allocationModifications) {
         List<ResourceAllocation<?>> result = new ArrayList<ResourceAllocation<?>>();
diff --git a/navalplanner-webapp/src/main/java/org/navalplanner/web/planner/allocation/AllocationRowsHandler.java b/navalplanner-webapp/src/main/java/org/navalplanner/web/planner/allocation/AllocationRowsHandler.java
index bc99c0ce2..92d857dc2 100644
--- a/navalplanner-webapp/src/main/java/org/navalplanner/web/planner/allocation/AllocationRowsHandler.java
+++ b/navalplanner-webapp/src/main/java/org/navalplanner/web/planner/allocation/AllocationRowsHandler.java
@@ -29,6 +29,7 @@ import java.util.Set;
 
 import org.joda.time.LocalDate;
 import org.navalplanner.business.calendars.entities.ThereAreHoursOnWorkHoursCalculator.CapacityResult;
+import org.navalplanner.business.common.Flagged;
 import org.navalplanner.business.orders.entities.HoursGroup;
 import org.navalplanner.business.planner.entities.CalculatedValue;
 import org.navalplanner.business.planner.entities.DerivedAllocationGenerator.IWorkerFinder;
@@ -229,7 +230,11 @@ public class AllocationRowsHandler {
         return result;
     }
 
-    public AllocationResult doAllocation() {
+    public enum Warnings {
+        SOME_GOALS_NOT_FULFILLED;
+    }
+
+    public Flagged<AllocationResult, Warnings> doAllocation() {
         checkInvalidValues();
         if (!currentRows.isEmpty()) {
             List<? extends AllocationModification> modificationsDone;
@@ -238,10 +243,20 @@ public class AllocationRowsHandler {
             AllocationRow.loadDataFromLast(currentRows, modificationsDone);
 
             createDerived();
+            AllocationResult result = createResult();
+            if (AllocationModification.allFullfiled(modificationsDone)) {
+                return Flagged.justValue(result);
+            } else {
+                return Flagged.withFlags(result,
+                        Warnings.SOME_GOALS_NOT_FULFILLED);
+            }
         }
-        AllocationResult result = AllocationResult.create(task,
+        return Flagged.justValue(createResult());
+    }
+
+    private AllocationResult createResult() {
+        return AllocationResult.create(task,
                 calculatedValue, currentRows, getWorkableDaysIfApplyable());
-        return result;
     }
 
     private List<? extends AllocationModification> doSuitableAllocation() {
diff --git a/navalplanner-webapp/src/main/java/org/navalplanner/web/planner/allocation/FormBinder.java b/navalplanner-webapp/src/main/java/org/navalplanner/web/planner/allocation/FormBinder.java
index 4c7281596..ad9f44e1a 100644
--- a/navalplanner-webapp/src/main/java/org/navalplanner/web/planner/allocation/FormBinder.java
+++ b/navalplanner-webapp/src/main/java/org/navalplanner/web/planner/allocation/FormBinder.java
@@ -34,6 +34,7 @@ import org.apache.commons.lang.Validate;
 import org.joda.time.LocalDate;
 import org.joda.time.format.DateTimeFormat;
 import org.joda.time.format.DateTimeFormatter;
+import org.navalplanner.business.common.Flagged;
 import org.navalplanner.business.common.ProportionalDistributor;
 import org.navalplanner.business.planner.entities.AggregateOfResourceAllocations;
 import org.navalplanner.business.planner.entities.CalculatedValue;
@@ -48,6 +49,7 @@ import org.navalplanner.web.common.Level;
 import org.navalplanner.web.common.Util;
 import org.navalplanner.web.common.components.NewAllocationSelectorCombo;
 import org.navalplanner.web.common.components.ResourceAllocationBehaviour;
+import org.navalplanner.web.planner.allocation.AllocationRowsHandler.Warnings;
 import org.navalplanner.web.planner.allocation.IResourceAllocationModel.IResourceAllocationContext;
 import org.navalplanner.web.planner.taskedition.TaskPropertiesController;
 import org.zkoss.util.Locales;
@@ -486,14 +488,35 @@ public class FormBinder {
     }
 
     public void doApply() {
-        lastAllocation = resourceAllocationModel
+        AllocationResult allocationResult = resourceAllocationModel
                 .onAllocationContext(new IResourceAllocationContext<AllocationResult>() {
 
                     @Override
                     public AllocationResult doInsideTransaction() {
-                        return allocationRowsHandler.doAllocation();
+                        return allocationRowsHandler.doAllocation().getValue();
                     }
                 });
+        allocationProduced(allocationResult);
+    }
+
+    /**
+     *
+     * @return <code>true</code> if and only if operation completed and must
+     *         exit the edition form
+     */
+    public boolean accept() {
+        Flagged<AllocationResult, Warnings> result = resourceAllocationModel
+                .accept();
+
+        // result can be null when editing milestones
+        if (result != null && result.isFlagged()) {
+            allocationProduced(result.getValue());
+        }
+        return result == null || !result.isFlagged();
+    }
+
+    private void allocationProduced(AllocationResult allocationResult) {
+        lastAllocation = allocationResult;
         aggregate = lastAllocation.getAggregate();
         allResourcesPerDayVisibilityRule();
         sumResourcesPerDayFromRowsAndAssignToAllResourcesPerDay();
@@ -861,5 +884,4 @@ public class FormBinder {
         this.behaviour = behaviour;
     }
 
-
 }
diff --git a/navalplanner-webapp/src/main/java/org/navalplanner/web/planner/allocation/IResourceAllocationModel.java b/navalplanner-webapp/src/main/java/org/navalplanner/web/planner/allocation/IResourceAllocationModel.java
index ef90b7405..8ad6e27f5 100644
--- a/navalplanner-webapp/src/main/java/org/navalplanner/web/planner/allocation/IResourceAllocationModel.java
+++ b/navalplanner-webapp/src/main/java/org/navalplanner/web/planner/allocation/IResourceAllocationModel.java
@@ -24,10 +24,12 @@ package org.navalplanner.web.planner.allocation;
 import java.util.Date;
 import java.util.List;
 
+import org.navalplanner.business.common.Flagged;
 import org.navalplanner.business.common.ProportionalDistributor;
 import org.navalplanner.business.orders.entities.AggregatedHoursGroup;
 import org.navalplanner.business.planner.entities.Task;
 import org.navalplanner.business.planner.entities.TaskElement;
+import org.navalplanner.web.planner.allocation.AllocationRowsHandler.Warnings;
 import org.navalplanner.web.planner.order.PlanningState;
 import org.zkoss.ganttz.extensions.IContextWithPlannerTask;
 
@@ -50,8 +52,10 @@ public interface IResourceAllocationModel extends INewAllocationsAdder {
 
     /**
      * Save task
+     *
+     * @return
      */
-    void accept();
+    Flagged<AllocationResult, Warnings> accept();
 
     /**
      * Starts the use case
diff --git a/navalplanner-webapp/src/main/java/org/navalplanner/web/planner/allocation/ResourceAllocationController.java b/navalplanner-webapp/src/main/java/org/navalplanner/web/planner/allocation/ResourceAllocationController.java
index 48c644446..85b2af27e 100644
--- a/navalplanner-webapp/src/main/java/org/navalplanner/web/planner/allocation/ResourceAllocationController.java
+++ b/navalplanner-webapp/src/main/java/org/navalplanner/web/planner/allocation/ResourceAllocationController.java
@@ -597,9 +597,17 @@ public class ResourceAllocationController extends GenericForwardComposer {
         allocationsGrid.setModel(new SimpleListModel(Collections.emptyList()));
     }
 
-    public void accept() {
-        resourceAllocationModel.accept();
-        clear();
+    /**
+     *
+     * @return <code>true</code> if it must exist <code>false</code> if exit
+     *         must be prevented
+     */
+    public boolean accept() {
+        boolean mustExit = formBinder.accept();
+        if (mustExit) {
+            clear();
+        }
+        return mustExit;
     }
 
     private class ResourceAllocationRenderer implements RowRenderer {
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 debaa778d..18cb1973e 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
@@ -28,6 +28,7 @@ import java.util.List;
 import java.util.Set;
 
 import org.hibernate.Hibernate;
+import org.navalplanner.business.common.Flagged;
 import org.navalplanner.business.common.IAdHocTransactionService;
 import org.navalplanner.business.common.IOnTransaction;
 import org.navalplanner.business.common.ProportionalDistributor;
@@ -39,11 +40,11 @@ import org.navalplanner.business.planner.daos.ITaskElementDAO;
 import org.navalplanner.business.planner.daos.ITaskSourceDAO;
 import org.navalplanner.business.planner.entities.DayAssignment;
 import org.navalplanner.business.planner.entities.DerivedAllocation;
+import org.navalplanner.business.planner.entities.DerivedAllocationGenerator.IWorkerFinder;
 import org.navalplanner.business.planner.entities.GenericResourceAllocation;
 import org.navalplanner.business.planner.entities.ResourceAllocation;
 import org.navalplanner.business.planner.entities.Task;
 import org.navalplanner.business.planner.entities.TaskElement;
-import org.navalplanner.business.planner.entities.DerivedAllocationGenerator.IWorkerFinder;
 import org.navalplanner.business.resources.daos.ICriterionDAO;
 import org.navalplanner.business.resources.daos.IResourceDAO;
 import org.navalplanner.business.resources.daos.IResourcesSearcher;
@@ -55,6 +56,7 @@ import org.navalplanner.business.resources.entities.MachineWorkersConfigurationU
 import org.navalplanner.business.resources.entities.Resource;
 import org.navalplanner.business.resources.entities.ResourceEnum;
 import org.navalplanner.business.resources.entities.Worker;
+import org.navalplanner.web.planner.allocation.AllocationRowsHandler.Warnings;
 import org.navalplanner.web.planner.order.PlanningState;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.beans.factory.config.BeanDefinition;
@@ -169,42 +171,52 @@ public class ResourceAllocationModel implements IResourceAllocationModel {
     }
 
     @Override
-    public void accept() {
+    public Flagged<AllocationResult, Warnings> accept() {
         if (context != null) {
-            applyAllocationWithDateChangesNotification(new IOnTransaction<Void>() {
+            return applyDateChangesNotificationIfNoFlags(new IOnTransaction<Flagged<AllocationResult, Warnings>>() {
                 @Override
-                public Void execute() {
+                public Flagged<AllocationResult, Warnings> execute() {
                     stepsBeforeDoingAllocation();
-                    allocationRowsHandler.doAllocation().applyTo(
-                            planningState.getCurrentScenario(), task);
-                    return null;
+                    Flagged<AllocationResult, Warnings> allocationResult = allocationRowsHandler
+                            .doAllocation();
+                    if (!allocationResult.isFlagged()) {
+                        allocationResult.getValue().applyTo(
+                                planningState.getCurrentScenario(), task);
+                    }
+                    return allocationResult;
                 }
             });
         }
+        return null;
     }
 
     @Override
     public void accept(final AllocationResult modifiedAllocationResult) {
         if (context != null) {
-            applyAllocationWithDateChangesNotification(new IOnTransaction<Void>() {
+            applyDateChangesNotificationIfNoFlags(new IOnTransaction<Flagged<Void, Void>>() {
                 @Override
-                public Void execute() {
+                public Flagged<Void, Void> execute() {
                     stepsBeforeDoingAllocation();
                     modifiedAllocationResult.applyTo(planningState
                             .getCurrentScenario(), task);
-                    return null;
+
+                    return Flagged.justValue(null);
                 }
             });
         }
     }
 
-    private void applyAllocationWithDateChangesNotification(
-            IOnTransaction<?> allocationDoer) {
+    private <V, T extends Flagged<V, ?>> T applyDateChangesNotificationIfNoFlags(
+            IOnTransaction<T> allocationDoer) {
         org.zkoss.ganttz.data.Task ganttTask = context.getTask();
         GanttDate previousStartDate = ganttTask.getBeginDate();
         GanttDate previousEnd = ganttTask.getEndDate();
-        transactionService.runOnReadOnlyTransaction(allocationDoer);
-        ganttTask.fireChangesForPreviousValues(previousStartDate, previousEnd);
+        T result = transactionService.runOnReadOnlyTransaction(allocationDoer);
+        if (!result.isFlagged()) {
+            ganttTask.fireChangesForPreviousValues(previousStartDate,
+                    previousEnd);
+        }
+        return result;
     }
 
     private void stepsBeforeDoingAllocation() {
diff --git a/navalplanner-webapp/src/main/java/org/navalplanner/web/planner/taskedition/EditTaskController.java b/navalplanner-webapp/src/main/java/org/navalplanner/web/planner/taskedition/EditTaskController.java
index 73c7b62c5..8caf496cf 100644
--- a/navalplanner-webapp/src/main/java/org/navalplanner/web/planner/taskedition/EditTaskController.java
+++ b/navalplanner-webapp/src/main/java/org/navalplanner/web/planner/taskedition/EditTaskController.java
@@ -282,7 +282,10 @@ public class EditTaskController extends GenericForwardComposer {
             ResourceAllocationTypeEnum currentState = taskPropertiesController.getCurrentState();
             if (ResourceAllocationTypeEnum.NON_LIMITING_RESOURCES.equals(currentState)) {
                 editTaskTabbox.setSelectedPanelApi(resourceAllocationTabpanel);
-                resourceAllocationController.accept();
+                boolean mustNotExit = !resourceAllocationController.accept();
+                if (mustNotExit) {
+                    return;
+                }
             } else if (ResourceAllocationTypeEnum.SUBCONTRACT.equals(currentState)) {
                 editTaskTabbox.setSelectedPanelApi(subcontractTabpanel);
                 subcontractController.accept();