diff --git a/libreplan-webapp/src/main/java/org/libreplan/web/workreports/IWorkReportModel.java b/libreplan-webapp/src/main/java/org/libreplan/web/workreports/IWorkReportModel.java
index 4fe200b8f..6fdf67f67 100644
--- a/libreplan-webapp/src/main/java/org/libreplan/web/workreports/IWorkReportModel.java
+++ b/libreplan-webapp/src/main/java/org/libreplan/web/workreports/IWorkReportModel.java
@@ -243,4 +243,6 @@ public interface IWorkReportModel extends IIntegrationEntityModel {
      */
     boolean isMonthlyTimesheet(WorkReport workReport);
 
+    WorkReportLine getFirstWorkReportLine();
+
 }
diff --git a/libreplan-webapp/src/main/java/org/libreplan/web/workreports/WorkReportCRUDController.java b/libreplan-webapp/src/main/java/org/libreplan/web/workreports/WorkReportCRUDController.java
index 0714d77f2..195197f13 100644
--- a/libreplan-webapp/src/main/java/org/libreplan/web/workreports/WorkReportCRUDController.java
+++ b/libreplan-webapp/src/main/java/org/libreplan/web/workreports/WorkReportCRUDController.java
@@ -630,7 +630,8 @@ public class WorkReportCRUDController extends GenericForwardComposer implements
     }
 
     private void goToEditMonthlyTimeSheet(WorkReport workReport) {
-        Date date = workReport.getWorkReportLines().iterator().next().getDate();
+        workReportModel.initEdit(workReport);
+        Date date = workReportModel.getFirstWorkReportLine().getDate();
         Resource resource = workReport.getResource();
         monthlyTimesheetController.goToCreateOrEditFormForResource(
                 LocalDate.fromDateFields(date), resource);
diff --git a/libreplan-webapp/src/main/java/org/libreplan/web/workreports/WorkReportModel.java b/libreplan-webapp/src/main/java/org/libreplan/web/workreports/WorkReportModel.java
index b82b38f28..1e5977a62 100644
--- a/libreplan-webapp/src/main/java/org/libreplan/web/workreports/WorkReportModel.java
+++ b/libreplan-webapp/src/main/java/org/libreplan/web/workreports/WorkReportModel.java
@@ -639,4 +639,9 @@ public class WorkReportModel extends IntegrationEntityModel implements
         }
     }
 
+    @Override
+    public WorkReportLine getFirstWorkReportLine() {
+        return workReport.getWorkReportLines().iterator().next();
+    }
+
 }