diff --git a/navalplanner-business/src/main/java/org/navalplanner/business/calendars/entities/BaseCalendar.java b/navalplanner-business/src/main/java/org/navalplanner/business/calendars/entities/BaseCalendar.java
index b9736f91e..00539b981 100644
--- a/navalplanner-business/src/main/java/org/navalplanner/business/calendars/entities/BaseCalendar.java
+++ b/navalplanner-business/src/main/java/org/navalplanner/business/calendars/entities/BaseCalendar.java
@@ -29,6 +29,7 @@ import java.util.HashSet;
 import java.util.List;
 import java.util.Set;
 
+import org.apache.commons.lang.ObjectUtils;
 import org.apache.commons.lang.StringUtils;
 import org.hibernate.validator.AssertTrue;
 import org.hibernate.validator.NotEmpty;
@@ -713,9 +714,16 @@ public class BaseCalendar extends IntegrationEntity implements ICalendar {
 
     public boolean isLastCalendarAvailability(
             CalendarAvailability calendarAvailability) {
-        return getLastCalendarAvailability() != null ? calendarAvailability
-                .getId() == getLastCalendarAvailability().getId()
-                : false;
+        if (getLastCalendarAvailability() == null
+                || calendarAvailability == null) {
+            return false;
+        }
+        if (getLastCalendarAvailability().getId() == null
+                && calendarAvailability.getId() == null) {
+            return getLastCalendarAvailability() == calendarAvailability;
+        }
+        return ObjectUtils.equals(getLastCalendarAvailability().getId(),
+                calendarAvailability.getId());
     }
 
     public void setStartDate(CalendarAvailability calendarAvailability,
diff --git a/navalplanner-webapp/src/main/java/org/navalplanner/web/calendars/BaseCalendarEditionController.java b/navalplanner-webapp/src/main/java/org/navalplanner/web/calendars/BaseCalendarEditionController.java
index 12e1392a5..b8f1df751 100644
--- a/navalplanner-webapp/src/main/java/org/navalplanner/web/calendars/BaseCalendarEditionController.java
+++ b/navalplanner-webapp/src/main/java/org/navalplanner/web/calendars/BaseCalendarEditionController.java
@@ -1216,10 +1216,10 @@ public abstract class BaseCalendarEditionController extends
 
         private LocalDate getAppropiateEndDate(
                 CalendarAvailability calendarAvailability, Date endDate) {
-            if(endDate == null){
+            if (endDate == null) {
                 if (baseCalendarModel
                         .isLastActivationPeriod(calendarAvailability)) {
-                                return null;
+                    return null;
                 } else {
                     throw new IllegalArgumentException(
                             _("Only the last activation period allows to delete end date."));