diff --git a/BookAStar/BookAStar.Droid/BookAStar.Droid.csproj b/BookAStar/BookAStar.Droid/BookAStar.Droid.csproj
index 9903e7bc..84e16c22 100644
--- a/BookAStar/BookAStar.Droid/BookAStar.Droid.csproj
+++ b/BookAStar/BookAStar.Droid/BookAStar.Droid.csproj
@@ -333,6 +333,7 @@
     <Compile Include="Helpers\SimpleJsonPostMethod.cs" />
     <Compile Include="Helpers\YavscHelpers.cs" />
     <Compile Include="Html.cs" />
+    <Compile Include="Interfaces\IGCMessageHandler.cs" />
     <Compile Include="MainActivity.cs" />
     <Compile Include="Markdown\JsBridgeMarkdown.cs" />
     <Compile Include="Markdown\MarkdownEditor.cs">
@@ -351,6 +352,8 @@
     <Compile Include="Properties\AssemblyInfo.cs" />
     <Compile Include="SendFilesActivity.cs" />
     <Compile Include="Services\AccountChooserService.cs" />
+    <Compile Include="Services\GCMHandlers\BookQueryGCMHandler.cs" />
+    <Compile Include="Services\GCMHandlers\GCMessageHandler.cs" />
     <Compile Include="Services\YavscChooserTargetService.cs" />
     <Compile Include="Services\GcmListenerService.cs" />
     <Compile Include="Services\GcmRegistrationIntentService.cs" />
diff --git a/BookAStar/BookAStar.Droid/Interfaces/IGCMessageHandler.cs b/BookAStar/BookAStar.Droid/Interfaces/IGCMessageHandler.cs
new file mode 100644
index 00000000..910347ae
--- /dev/null
+++ b/BookAStar/BookAStar.Droid/Interfaces/IGCMessageHandler.cs
@@ -0,0 +1,19 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+using Android.App;
+using Android.Content;
+using Android.OS;
+using Android.Runtime;
+using Android.Views;
+using Android.Widget;
+
+namespace BookAStar.Droid.Interfaces
+{
+    interface IGCMessageHandler
+    {
+        void Handle( string from, Bundle data);
+    }
+}
\ No newline at end of file
diff --git a/BookAStar/BookAStar.Droid/Services/GCMHandlers/BookQueryGCMHandler.cs b/BookAStar/BookAStar.Droid/Services/GCMHandlers/BookQueryGCMHandler.cs
new file mode 100644
index 00000000..d5168faa
--- /dev/null
+++ b/BookAStar/BookAStar.Droid/Services/GCMHandlers/BookQueryGCMHandler.cs
@@ -0,0 +1,88 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+using Android.App;
+using Android.Content;
+using Android.OS;
+using Android.Runtime;
+using Android.Views;
+using Android.Widget;
+using BookAStar.Droid.Interfaces;
+using Newtonsoft.Json;
+using BookAStar.Model.Social;
+using BookAStar.Data;
+using BookAStar.Model;
+
+namespace BookAStar.Droid.Services.GCMHandlers
+{
+    class BookQueryGCMHandler : GCMessageHandler
+    {
+        public BookQueryGCMHandler(Context context,
+            NotificationManager manager,
+            Notification.Builder builder) : base(context,manager,builder)
+        {
+
+        }
+
+        public override void Handle(string from, Bundle data)
+        {
+            var locationJson = data.GetString("Location");
+            var location = JsonConvert.DeserializeObject<Location>(locationJson);
+            var cid = long.Parse(data.GetString("Id"));
+            var clientJson = data.GetString("Client");
+            var client = JsonConvert.DeserializeObject<ClientProviderInfo>(clientJson);
+            var bq = new BookQuery
+            {
+                Id = cid,
+                Location = location,
+                Client = client,
+                Reason = data.GetString("Reason")
+            };
+            var dateString = data.GetString("EventDate");
+            DateTime evDate;
+            if (DateTime.TryParse(dateString, out evDate))
+            {
+                bq.EventDate = evDate;
+            }
+            SendBookQueryNotification(bq);
+        }
+
+        void SendBookQueryNotification(BookQuery bquery)
+        {
+            DataManager.Instance.BookQueries.Merge(bquery);
+            var bookquerynotifications = DataManager.Instance.BookQueries.Where(
+                q => !q.Read && q.EventDate > DateTime.Now
+                ).ToArray();
+            var count = bookquerynotifications.Length;
+            var multiple = count > 1;
+            var title =
+            multiple ? $"{count} demandes" : bquery.Client.UserName;
+            var message = $"{bquery.EventDate} {bquery.Client.UserName} {bquery.Location.Address}\n {bquery.Reason}";
+
+            var intent = new Intent(context, typeof(MainActivity));
+            intent.AddFlags(ActivityFlags.ClearTop);
+            intent.PutExtra("BookQueryId", bquery.Id);
+
+            var pendingIntent = PendingIntent.GetActivity(context, 0, intent, PendingIntentFlags.OneShot);
+            Notification.InboxStyle inboxStyle = new Notification.InboxStyle();
+            int maxil = 5;
+            for (int cn = 0; cn < count && cn < maxil; cn++)
+            {
+                inboxStyle.AddLine(bookquerynotifications[cn].Client.UserName);
+            }
+            if (count > maxil)
+                inboxStyle.SetSummaryText($"Plus {count - maxil} autres");
+            else inboxStyle.SetSummaryText((string)null);
+            notificationBuilder.SetContentTitle(title).SetContentText(message)
+                .SetStyle(inboxStyle)
+                .SetContentIntent(pendingIntent);
+
+            var notification = notificationBuilder.Build();
+            notificationManager.Notify(bookQueryNotificationId, notification);
+        }
+
+        int bookQueryNotificationId = 1;
+    }
+}
diff --git a/BookAStar/BookAStar.Droid/Services/GCMHandlers/GCMessageHandler.cs b/BookAStar/BookAStar.Droid/Services/GCMHandlers/GCMessageHandler.cs
new file mode 100644
index 00000000..de9c0e6f
--- /dev/null
+++ b/BookAStar/BookAStar.Droid/Services/GCMHandlers/GCMessageHandler.cs
@@ -0,0 +1,32 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+using Android.App;
+using Android.Content;
+using Android.OS;
+using Android.Runtime;
+using Android.Views;
+using Android.Widget;
+using BookAStar.Droid.Interfaces;
+
+namespace BookAStar.Droid.Services.GCMHandlers
+{
+    abstract class GCMessageHandler : IGCMessageHandler
+    {
+        protected Context context;
+        protected NotificationManager notificationManager;
+        protected Notification.Builder notificationBuilder;
+        public GCMessageHandler(Context context,
+            NotificationManager notificationManager,
+            Notification.Builder notificationBuilder)
+        {
+            this.context = context;
+            this.notificationBuilder = notificationBuilder;
+            this.notificationManager = notificationManager;
+        }
+
+        public abstract void Handle(string from, Bundle data);
+    }
+}
\ No newline at end of file
diff --git a/BookAStar/BookAStar.Droid/Services/GcmListenerService.cs b/BookAStar/BookAStar.Droid/Services/GcmListenerService.cs
index 83df3daa..e8648d5a 100644
--- a/BookAStar/BookAStar.Droid/Services/GcmListenerService.cs
+++ b/BookAStar/BookAStar.Droid/Services/GcmListenerService.cs
@@ -1,17 +1,20 @@
+
+using Android.App;
+using Android.Content;
+using Android.OS;
+using Android.Gms.Gcm;
+using Newtonsoft.Json;
 using System;
+using System.Collections.Generic;
+using System.Linq;
 
 namespace BookAStar.Droid.Services
 {
-    using Android.App;
-    using Android.Content;
-    using Android.OS;
-    using Android.Gms.Gcm;
     using Model.Social;
-    using Newtonsoft.Json;
     using Model;
-    using Model.Social;
     using Data;
-    using System.Linq;
+    using Interfaces;
+    using GCMHandlers;
 
     namespace ClientApp
     {
@@ -21,7 +24,7 @@ namespace BookAStar.Droid.Services
             private Notification.Builder notificationBuilder;
 
             NotificationManager notificationManager;
-            
+            Dictionary<string, IGCMessageHandler> Handlers;
             public override void OnCreate()
             {
                 base.OnCreate();
@@ -29,7 +32,10 @@ namespace BookAStar.Droid.Services
                     .SetSmallIcon(Resource.Drawable.icon)
                     .SetAutoCancel(true);
                 notificationManager = (NotificationManager)GetSystemService(Context.NotificationService);
-                
+                Handlers = new Dictionary<string, IGCMessageHandler>
+                {
+                    {"BookQuery", new BookQueryGCMHandler(this,notificationManager,notificationBuilder) }
+                };
             }
 
             public override void OnDestroy()
@@ -44,39 +50,16 @@ namespace BookAStar.Droid.Services
             public override void OnMessageReceived(string from, Bundle data)
             {
                 var topic = data.GetString("Topic");
-                if (topic == "BookQuery")
+                if (Handlers.ContainsKey(topic))
                 {
-                    DateTime eventdate;
-                    var sdatestr = data.GetString("EventDate");
-                    DateTime.TryParse(sdatestr, out eventdate);
-
-                    var locationJson = data.GetString("Location");
-                    var location = JsonConvert.DeserializeObject<Location>(locationJson);
-                    var cid = long.Parse(data.GetString("Id"));
-                    var clientJson = data.GetString("Client");
-                    var client = JsonConvert.DeserializeObject<ClientProviderInfo>(clientJson);
-                    var bq = new BookQuery
-                    {
-                        Id = cid,
-                        Location = location,
-                        Client = client,
-                        Reason = data.GetString("Reason")
-                    };
-                    var dateString = data.GetString("EventDate");
-                    DateTime evDate;
-                    if (DateTime.TryParse(dateString, out evDate))
-                    {
-                        bq.EventDate = evDate;
-                    }
-
-                    SendBookQueryNotification(bq);
+                    Handlers[topic].Handle(from, data);
                 }
                 else
                 {
                     throw new NotImplementedException(topic);
                 }
             }
-
+            /* TODO cleaning
             void SendNotification(string title, string message)
             {
                 var intent = new Intent(this, typeof(MainActivity));
@@ -92,43 +75,8 @@ namespace BookAStar.Droid.Services
                     .SetContentIntent(pendingIntent);
 
                 notificationManager.Notify(0, notificationBuilder.Build());
-            }
-
-            void SendBookQueryNotification(BookQuery bquery)
-            {
-                DataManager.Instance.BookQueries.Merge(bquery);
-                var bookquerynotifications = DataManager.Instance.BookQueries.Where(
-                    q=> ! q.Read && q.EventDate > DateTime.Now 
-                    ).ToArray();
-                var count = bookquerynotifications.Length;
-                var multiple = count > 1;
-                var title =
-                multiple ? $"{count} demandes" : bquery.Client.UserName;
-                var message = $"{bquery.EventDate} {bquery.Client.UserName} {bquery.Location.Address}\n {bquery.Reason}";
-
-                var intent = new Intent(this, typeof(MainActivity));
-                intent.AddFlags(ActivityFlags.ClearTop);
-                intent.PutExtra("BookQueryId", bquery.Id);
-               
-                var pendingIntent = PendingIntent.GetActivity(this, 0, intent, PendingIntentFlags.OneShot);
-                Notification.InboxStyle inboxStyle = new Notification.InboxStyle();
-                int maxil = 5;
-                for (int cn = 0; cn < count && cn < maxil; cn++)
-                {
-                    inboxStyle.AddLine(bookquerynotifications[cn].Client.UserName);
-                }
-                if (count > maxil)
-                    inboxStyle.SetSummaryText($"Plus {count - maxil} autres");
-                else inboxStyle.SetSummaryText((string)null);
-                notificationBuilder.SetContentTitle(title).SetContentText(message)
-                    .SetStyle(inboxStyle)
-                    .SetContentIntent(pendingIntent);
-
-                var notification = notificationBuilder.Build();
-                notificationManager.Notify(bookQueryNotificationId, notification );
-            }
-
-            int bookQueryNotificationId=1;
+            }*/
         }
+            
     }
 }
\ No newline at end of file
diff --git a/BookAStar/BookAStar/BookAStar.csproj b/BookAStar/BookAStar/BookAStar.csproj
index 1687641c..a18bdd2d 100644
--- a/BookAStar/BookAStar/BookAStar.csproj
+++ b/BookAStar/BookAStar/BookAStar.csproj
@@ -166,7 +166,7 @@
     <Compile Include="Model\Blog\BlogTag.cs" />
     <Compile Include="Model\Booking\BookQuery.cs" />
     <Compile Include="Model\Market\BaseProduct.cs" />
-    <Compile Include="Model\Workflow\BillingLine.cs" />
+    <Compile Include="Pages\EstimatePages\BillingLine.cs" />
     <Compile Include="Model\Manager.cs" />
     <Compile Include="Model\Auth\MobileAppDeclaration.cs" />
     <Compile Include="Model\Auth\passwrecovery.cs" />
diff --git a/BookAStar/BookAStar/Model/Booking/BookQuery.cs b/BookAStar/BookAStar/Model/Booking/BookQuery.cs
index 67721c49..a40eb9d7 100644
--- a/BookAStar/BookAStar/Model/Booking/BookQuery.cs
+++ b/BookAStar/BookAStar/Model/Booking/BookQuery.cs
@@ -5,12 +5,38 @@ namespace BookAStar.Model.Social
 {
     public class BookQuery 
     {
+        /// <summary>
+        /// Client having made this book query.
+        /// </summary>
         public ClientProviderInfo Client { get; set; }
+        /// <summary>
+        /// Location of the client event
+        /// </summary>
         public Location Location { get; set; }
+        /// <summary>
+        /// Unique identifier
+        /// </summary>
         public long Id { get; set; }
+        /// <summary>
+        /// Date of the client event
+        /// </summary>
         public DateTime EventDate { get; set; }
+        /// <summary>
+        /// Amount of money already available, from the site bank, for this event project.
+        /// </summary>
         public decimal? Previsionnal { get; set; }
+        /// <summary>
+        /// Given reason from the client
+        /// </summary>
         public string Reason { get; set; }
+        /// <summary>
+        /// True when the query has been read.
+        /// </summary>
         public bool Read { get; set; }
+        /// <summary>
+        /// Unique identifier of the activity concerned, 
+        /// the context of this query.
+        /// </summary>
+        public string ActivityCode { get; set; }
     }
 }
diff --git a/BookAStar/BookAStar/Model/Workflow/BillingLine.cs b/BookAStar/BookAStar/Pages/EstimatePages/BillingLine.cs
similarity index 100%
rename from BookAStar/BookAStar/Model/Workflow/BillingLine.cs
rename to BookAStar/BookAStar/Pages/EstimatePages/BillingLine.cs
diff --git a/BookAStar/BookAStar/Pages/EstimatePages/EditEstimatePage.xaml.cs b/BookAStar/BookAStar/Pages/EstimatePages/EditEstimatePage.xaml.cs
index 163d8b12..a8f7ef58 100644
--- a/BookAStar/BookAStar/Pages/EstimatePages/EditEstimatePage.xaml.cs
+++ b/BookAStar/BookAStar/Pages/EstimatePages/EditEstimatePage.xaml.cs
@@ -115,8 +115,9 @@ namespace BookAStar.Pages
                 Strings.CancelValidation, new string[] { Strings.Sign  });
             if (response == Strings.Sign)
             {
-                App.NavigationService.NavigateTo<EstimateSigningPage>(true, 
-                    new EstimateSigningViewModel(evm.Data) { ValidationCommand = cmd });
+                App.NavigationService.NavigateTo<EstimateSigningPage>(true,
+                    new EstimateSigningViewModel(evm.Data) { ValidationCommand = cmd,
+                        IsProviderView = true });
             }
             else if (response == Strings.CancelValidation)
                 return;
diff --git a/BookAStar/BookAStar/ViewModels/Signing/EstimateSigningViewModel.cs b/BookAStar/BookAStar/ViewModels/Signing/EstimateSigningViewModel.cs
index 20989946..e615d55a 100644
--- a/BookAStar/BookAStar/ViewModels/Signing/EstimateSigningViewModel.cs
+++ b/BookAStar/BookAStar/ViewModels/Signing/EstimateSigningViewModel.cs
@@ -9,13 +9,16 @@ namespace BookAStar.ViewModels.Signing
         public EstimateSigningViewModel(Estimate document): base(document)
         {
         }
+
         public Command<bool> ValidationCommand { get; set; }
+
         public ImageSource ProSignImage {
             get
             {
                 return new FileImageSource();
             }
         }
+
         public ImageSource CliSignImage
         {
             get
@@ -23,5 +26,43 @@ namespace BookAStar.ViewModels.Signing
                 return new FileImageSource();
             }
         }
+
+        private bool isClientView=false;
+
+        public bool IsClientView {
+            get
+            {
+                return isClientView;
+            }
+            set {
+                bool old = isClientView;
+                SetProperty<bool>(ref isClientView, value);
+                if (old!=value)
+                {
+                    if (value != !isProviderView)
+                        IsProviderView = !value;
+                }
+            }
+        }
+
+        private bool isProviderView=true;
+
+        public bool IsProviderView
+        {
+            get
+            {
+                return isProviderView;
+            }
+            set
+            {
+                bool old = isProviderView;
+                SetProperty<bool>(ref isProviderView, value);
+                if (old != value)
+                {
+                    if (value != !isClientView)
+                        IsClientView = !value;
+                }
+            }
+        }
     }
 }