diff --git a/BookAStar/BookAStar.Droid/MainActivity.cs b/BookAStar/BookAStar.Droid/MainActivity.cs
index 3e632343..a170881a 100644
--- a/BookAStar/BookAStar.Droid/MainActivity.cs
+++ b/BookAStar/BookAStar.Droid/MainActivity.cs
@@ -107,8 +107,8 @@ namespace BookAStar.Droid
 
             LoadApplication(fapp);
 
-            CheckSharing();
-
+            var componentName = StartService(new Intent(this, typeof(YavscChooserTargetService)));
+            
             // TabLayoutResource = Resource.Layout.Tabbar;
             // ToolbarResource = Resource.Layout.Toolbar;
             /*
diff --git a/BookAStar/BookAStar.Droid/Properties/AndroidManifest.xml b/BookAStar/BookAStar.Droid/Properties/AndroidManifest.xml
index e9ef000a..1e31870f 100644
--- a/BookAStar/BookAStar.Droid/Properties/AndroidManifest.xml
+++ b/BookAStar/BookAStar.Droid/Properties/AndroidManifest.xml
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="utf-8"?>
 <manifest xmlns:android="http://schemas.android.com/apk/res/android" android:versionCode="1" android:versionName="1.0" package="fr.pschneider.bas" android:installLocation="auto">
 	<uses-sdk android:minSdkVersion="15" />
-	<application android:label="BookAStar" android:icon="@drawable/icon" android:theme="@style/MainTheme">
+	<application android:allowBackup="true" android:label="Booking Star" android:icon="@drawable/icon" android:theme="@style/MainTheme">
 		<meta-data android:name="com.google.android.maps.v2.API_KEY" android:value="AIzaSyBLSEDhZixwpHDsWmO2pKwgGDJReoTuQ7A" />
 		<meta-data android:name="com.google.android.gms.version" android:value="@integer/google_play_services_version" />
 		<receiver android:name="com.google.android.gms.gcm.GcmReceiver" android:exported="true" android:permission="com.google.android.c2dm.permission.SEND">
@@ -17,21 +17,19 @@
 				<category android:name="android.intent.category.LAUNCHER" />
 			</intent-filter>
 		</activity>
-		<service android:name="fr.pschneider.bas.YavscChooserTargetService" 
-             android:label="@string/app_name" 
-             android:permission="android.permission.BIND_CHOOSER_TARGET_SERVICE">
-			<intent-filter>
-				<action android:name="android.service.chooser.ChooserTargetService" />
-			</intent-filter>
-		</service>
 		<activity android:name="fr.pschneider.bas.SendFilesActivity" android:label="@string/app_name">
 			<intent-filter>
 				<action android:name="android.intent.action.SEND" />
 				<category android:name="android.intent.category.DEFAULT" />
-				<data android:mimeType="text/plain" />
+				<!-- <data android:mimeType="text/plain" /> -->
 			</intent-filter>
 			<meta-data android:name="android.service.chooser.chooser_target_service" android:value="fr.pschneider.bas.YavscChooserTargetService" />
 		</activity>
+		<service android:name="fr.pschneider.bas.YavscChooserTargetService" android:label="@string/app_name" android:permission="android.permission.BIND_CHOOSER_TARGET_SERVICE">
+			<intent-filter>
+				<action android:name="android.service.chooser.ChooserTargetService" />
+			</intent-filter>
+		</service>
 	</application>
 	<uses-permission android:name="android.permission.INTERNET" />
 	<uses-permission android:name="android.permission.WAVE_LOCK" />
diff --git a/BookAStar/BookAStar.Droid/Services/YavscChooserTargetService.cs b/BookAStar/BookAStar.Droid/Services/YavscChooserTargetService.cs
index c18fba3e..36c14393 100644
--- a/BookAStar/BookAStar.Droid/Services/YavscChooserTargetService.cs
+++ b/BookAStar/BookAStar.Droid/Services/YavscChooserTargetService.cs
@@ -10,10 +10,19 @@ using Android.Runtime;
 using Android.Views;
 using Android.Widget;
 using Android.Service.Chooser;
+using static Android.Manifest;
 
 namespace BookAStar.Droid
 {
-    [Service(Name = "fr.pschneider.bas.YavscChooserTargetService", Label = "Yavsc share service", Permission = "android.permission.BIND_CHOOSER_TARGET_SERVICE", Icon = "@drawable/icon", Exported = true)]
+    [Service(
+        Name = "fr.pschneider.bas.YavscChooserTargetService", 
+        Label = "Yavsc share service", 
+        Permission = Permission.BindChooserTargetService, 
+        Icon = "@drawable/icon", 
+        Exported = true,
+        Enabled = true
+        )]
+    [IntentFilter(new String[] { "android.service.chooser.ChooserTargetService" })]
     class YavscChooserTargetService : ChooserTargetService
     {
         public override IList<ChooserTarget> OnGetChooserTargets(ComponentName targetActivityName, IntentFilter matchedFilter)
@@ -24,7 +33,7 @@ namespace BookAStar.Droid
             ChooserTarget t = new ChooserTarget(
                 new Java.Lang.String(
                 "BookingStar"), i,
-                .5f, new ComponentName(this.BaseContext, ".SendFilesActivity"),
+                .5f, new ComponentName(this, "BookAStar.SendFilesActivity"),
                 null);
             var res = new List<ChooserTarget>();
             res.Add(t);
@@ -35,10 +44,5 @@ namespace BookAStar.Droid
         {
             return base.OnBind(intent);
         }
-
-        public override void OnCreate()
-        {
-            base.OnCreate();
-        }
     }
 }
\ No newline at end of file
diff --git a/BookAStar/BookAStar/App.xaml b/BookAStar/BookAStar/App.xaml
index cda14e18..31426f3f 100644
--- a/BookAStar/BookAStar/App.xaml
+++ b/BookAStar/BookAStar/App.xaml
@@ -23,7 +23,7 @@
       
       <OnPlatform x:TypeArguments="Font" Android="Large" iOS="Large" WinPhone="Large" x:Key="HeaderFont" />
       <OnPlatform x:TypeArguments="Color" Android="Red" iOS="Red" WinPhone="Red" x:Key="EmphasisTextColor" />
-      <OnPlatform x:TypeArguments="Font" Android="60" iOS="60" WinPhone="60" x:Key="LargeFontSize" />
+      <OnPlatform x:TypeArguments="Font" Android="90" iOS="90" WinPhone="90" x:Key="LargeFontSize" />
       <OnPlatform x:TypeArguments="Font" Android="50" iOS="50" WinPhone="50" x:Key="MediumFontSize" />
       <OnPlatform x:TypeArguments="Font" Android="40" iOS="40" WinPhone="40" x:Key="SmallFontSize" />
       <OnPlatform x:TypeArguments="x:Double" Android="130" iOS="130" WinPhone="130" x:Key="BigUserAvatarSize" />
diff --git a/BookAStar/BookAStar/App.xaml.cs b/BookAStar/BookAStar/App.xaml.cs
index a5123f7b..cb690f7e 100644
--- a/BookAStar/BookAStar/App.xaml.cs
+++ b/BookAStar/BookAStar/App.xaml.cs
@@ -85,6 +85,7 @@ namespace BookAStar
         {
             // TODO save the navigation stack
             int position = 0;
+            
             foreach (Page page in MainPage.Navigation.NavigationStack)
             {
 
diff --git a/BookAStar/BookAStar/BookAStar.csproj b/BookAStar/BookAStar/BookAStar.csproj
index 77fb0a15..75f2f26a 100644
--- a/BookAStar/BookAStar/BookAStar.csproj
+++ b/BookAStar/BookAStar/BookAStar.csproj
@@ -48,7 +48,9 @@
     <Compile Include="Behaviors\PickerBehavior.cs" />
     <Compile Include="Behaviors\StarBehavior.cs" />
     <Compile Include="Constants.cs" />
+    <Compile Include="Data\LocalState.cs" />
     <Compile Include="Model\UI\PageState.cs" />
+    <Compile Include="ViewModels\EditingViewModel.cs" />
     <Compile Include="Views\EnumPicker.cs" />
     <Compile Include="Converters\BooleanToObjectConverter.cs" />
     <Compile Include="Converters\EnumConverter.cs" />
diff --git a/BookAStar/BookAStar/Data/DataManager.cs b/BookAStar/BookAStar/Data/DataManager.cs
index a2a45205..1a478437 100644
--- a/BookAStar/BookAStar/Data/DataManager.cs
+++ b/BookAStar/BookAStar/Data/DataManager.cs
@@ -1,12 +1,11 @@
-using System.Threading.Tasks;
-
-namespace BookAStar.Data
+namespace BookAStar.Data
 {
     using Model;
     using Model.Blog;
     using Model.Workflow;
     using Model.UI;
-    
+    using ViewModels;
+
     public class DataManager
     {
         // TODO estimatetemplate rating service product tag   
@@ -15,11 +14,20 @@ namespace BookAStar.Data
         public RemoteEntity<Blog, long> Blogspot { get; set; }
         public LocalEntity<ClientProviderInfo,string> Contacts { get; set; }
         internal LocalEntity<PageState, int> AppState { get; set; }
-        protected static DataManager current = new DataManager();
+        /// <summary>
+        /// They have no remote exisence ...
+        /// </summary>
+        internal LocalEntity<EditEstimateViewModel, long> EstimationCache { get; set; }
+        internal LocalEntity<BillingLine, string> EstimateLinesTemplates { get; set; }
+
+        protected static DataManager current ;
+
         public static DataManager Current 
         {
             get
             {
+                if (current == null)
+                    current = new DataManager();
                 return current;
             }
         }
@@ -34,17 +42,17 @@ namespace BookAStar.Data
                 x=>x.Id);
             Contacts = new LocalEntity<ClientProviderInfo, string>(c => c.UserId);
             AppState = new LocalEntity<PageState, int>(s => s.Position);
-
+            EstimationCache = new LocalEntity<EditEstimateViewModel, long>(
+                e => e.Query.Id);
+            EstimateLinesTemplates = new LocalEntity<BillingLine, string>(
+                l => l.Description);
             BookQueries.Load();
             Estimates.Load();
             Blogspot.Load();
             Contacts.Load();
             AppState.Load();
-        }
-
-        public async Task<BookQueryData> GetBookQuery(long bookQueryId)
-        {
-            return await BookQueries.Get(bookQueryId);
+            EstimationCache.Load();
+            EstimateLinesTemplates.Load();
         }
     }
 }
diff --git a/BookAStar/BookAStar/Data/LocaLEntity.cs b/BookAStar/BookAStar/Data/LocaLEntity.cs
index 2030bab6..05ee3d58 100644
--- a/BookAStar/BookAStar/Data/LocaLEntity.cs
+++ b/BookAStar/BookAStar/Data/LocaLEntity.cs
@@ -32,6 +32,8 @@ namespace BookAStar.Data
 
         public V LocalGet(K key)
         {
+            if (!this.Any(x => GetKey(x).Equals(key)))
+                return default(V);
             CurrentItem = this.Single(x => GetKey(x).Equals(key));
             return CurrentItem;
         }
diff --git a/BookAStar/BookAStar/Data/LocalState.cs b/BookAStar/BookAStar/Data/LocalState.cs
new file mode 100644
index 00000000..bdb82ae7
--- /dev/null
+++ b/BookAStar/BookAStar/Data/LocalState.cs
@@ -0,0 +1,16 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace BookAStar.Data
+{
+    public enum LocalState
+    {
+        UpToDate = 0,
+        New,
+        Edited,
+        Removed
+    }
+}
diff --git a/BookAStar/BookAStar/Data/RemoteEntity.cs b/BookAStar/BookAStar/Data/RemoteEntity.cs
index 138b6143..ce70e52b 100644
--- a/BookAStar/BookAStar/Data/RemoteEntity.cs
+++ b/BookAStar/BookAStar/Data/RemoteEntity.cs
@@ -10,19 +10,19 @@ namespace BookAStar.Data
 {
     using Helpers;
 
-    public class RemoteEntity<V,K> : LocalEntity<V, K>, ICommand where K : IEquatable<K>
+    public class RemoteEntity<V, K> : LocalEntity<V, K>, ICommand where K : IEquatable<K>
     {
         private string _controller;
         public event EventHandler CanExecuteChanged;
         public bool IsExecuting { get; private set; }
-        
+
         private Uri controllerUri;
         public bool CanExecute(object parameter)
         {
             return !IsExecuting && (MainSettings.CurrentUser != null);
         }
 
-        public RemoteEntity(string controllerName, Func<V,K> getKey):base(getKey)
+        public RemoteEntity(string controllerName, Func<V, K> getKey) : base(getKey)
         {
             if (string.IsNullOrWhiteSpace(controllerName))
                 throw new InvalidOperationException();
@@ -35,7 +35,8 @@ namespace BookAStar.Data
             if (IsExecuting)
                 throw new InvalidOperationException("Already executing");
             IsExecuting = true;
-            CanExecuteChanged.Invoke(this, new EventArgs());
+            if (CanExecuteChanged != null)
+                CanExecuteChanged.Invoke(this, new EventArgs());
         }
 
         /// <summary>
@@ -65,7 +66,8 @@ namespace BookAStar.Data
                         }
                     }
                 }
-                catch (WebException webex) {
+                catch (WebException webex)
+                {
                     throw new ServiceNotAvailable("No remote entity", webex);
                 }
 
@@ -76,25 +78,26 @@ namespace BookAStar.Data
         private void AfterExecuting()
         {
             IsExecuting = false;
-            CanExecuteChanged.Invoke(this, new EventArgs());
+            if (CanExecuteChanged!=null)
+                CanExecuteChanged.Invoke(this, new EventArgs());
         }
 
         public async Task<V> Get(K key)
         {
             var item = LocalGet(key);
-            if (item==null) item = await RemoteGet(key);
+            if (item == null) item = await RemoteGet(key);
             CurrentItem = item;
             return CurrentItem;
         }
 
         public async Task<V> RemoteGet(K key)
         {
-           V item = default(V);
-           BeforeExecute();
+            V item = default(V);
+            BeforeExecute();
             // Get the whole data
-            var uri = new Uri(controllerUri.AbsolutePath+"/"+key.ToString());
+            var uri = new Uri(controllerUri.AbsoluteUri + "/" + key.ToString());
 
-            using (HttpClient client = new HttpClient())
+            using (HttpClient client = UserHelpers.CreateClient())
             {
                 using (var response = await client.GetAsync(uri))
                 {
@@ -111,6 +114,30 @@ namespace BookAStar.Data
             CurrentItem = item;
             return item;
         }
-        
+
+        public async void Create(V item)
+        {
+            BeforeExecute();
+
+            using (HttpClient client = UserHelpers.CreateClient())
+            {
+                HttpContent content = new StringContent(
+                    JsonConvert.SerializeObject(item)
+                    );
+                using (var response = await client.PostAsync(controllerUri, content))
+                {
+                    if (!response.IsSuccessStatusCode)
+                        // TODO throw custom exception, and catch to inform user
+                        throw new Exception($"Create failed posting {item} @ {controllerUri.AbsolutePath}");
+                    var recontent = await response.Content.ReadAsStringAsync();
+                    JsonConvert.PopulateObject(recontent, item);
+
+                }
+            }
+
+            AfterExecuting();
+            CurrentItem = item;
+        }
+
     }
 }
diff --git a/BookAStar/BookAStar/Helpers/MainSettings.cs b/BookAStar/BookAStar/Helpers/MainSettings.cs
index 2f8bbd75..0e573ac7 100644
--- a/BookAStar/BookAStar/Helpers/MainSettings.cs
+++ b/BookAStar/BookAStar/Helpers/MainSettings.cs
@@ -156,12 +156,14 @@ namespace BookAStar
                     if (olduserid != value.Id)
                     {
                         App.CurrentApp.PostDeviceInfo();
-                        UserChanged.Invoke(App.CurrentApp, new EventArgs());
+                        if (UserChanged!=null)
+                            UserChanged.Invoke(App.CurrentApp, new EventArgs());
                     }
                 }
                 else if (olduserid != null)
                 {
-                    UserChanged.Invoke(App.CurrentApp, new EventArgs());
+                    if (UserChanged != null)
+                        UserChanged.Invoke(App.CurrentApp, new EventArgs());
                     // TODO else Unregister this device
                 }
             }
@@ -267,7 +269,7 @@ namespace BookAStar
         {
             var key = $"{EntityDataSettingsPrefix}/{subKey}/{typeof(V).FullName}";
             var data = AppSettings.GetValueOrDefault<string>(key, null);
-            if (data != null)
+            if (!string.IsNullOrWhiteSpace(data))
             {
                 var items = JsonConvert.DeserializeObject<IList<V>>(data);
                 if (items != null)
diff --git a/BookAStar/BookAStar/Model/UI/PageState.cs b/BookAStar/BookAStar/Model/UI/PageState.cs
index d5baed26..186da6da 100644
--- a/BookAStar/BookAStar/Model/UI/PageState.cs
+++ b/BookAStar/BookAStar/Model/UI/PageState.cs
@@ -1,4 +1,6 @@
-namespace BookAStar.Model.UI
+using XLabs.Forms.Mvvm;
+
+namespace BookAStar.Model.UI
 {
     internal class PageState
     {
diff --git a/BookAStar/BookAStar/Model/Workflow/Estimate.cs b/BookAStar/BookAStar/Model/Workflow/Estimate.cs
index 578e82b3..277168f7 100644
--- a/BookAStar/BookAStar/Model/Workflow/Estimate.cs
+++ b/BookAStar/BookAStar/Model/Workflow/Estimate.cs
@@ -1,6 +1,7 @@
 using BookAStar.Data;
 using BookAStar.Helpers;
 using BookAStar.Model.Interfaces;
+using Newtonsoft.Json;
 using System.Collections.Generic;
 using System.Linq;
 
@@ -24,7 +25,7 @@ namespace BookAStar.Model.Workflow
         /// </summary>
         /// <returns></returns>
         public IList<string> AttachedGraphics { get; set; }
-
+        [JsonIgnore]
         public string AttachedGraphicsString
         {
             get { return AttachedGraphics==null?null:string.Join(":", AttachedGraphics); }
@@ -38,6 +39,7 @@ namespace BookAStar.Model.Workflow
         /// </summary>
         /// <returns></returns>
         public IList<string> AttachedFiles { get; set; }
+        [JsonIgnore]
         public string AttachedFilesString
         {
             get { return AttachedFiles == null ? null : string.Join(":", AttachedFiles); }
@@ -47,19 +49,20 @@ namespace BookAStar.Model.Workflow
         public string OwnerId { get; set; }
         
         public string ClientId { get; set; }
-        
+        [JsonIgnore]
         public BookQueryData Query
         {
             get
             {
                 if (CommandId.HasValue)
                 {
-                    return DataManager.Current.BookQueries.LocalGet(CommandId.Value);
+                    var dm = DataManager.Current;
+                    return dm.BookQueries.LocalGet(CommandId.Value);
                 }
                 return null;
             }
         }
-
+        [JsonIgnore]
         public ClientProviderInfo Client
         {
             get
@@ -68,7 +71,7 @@ namespace BookAStar.Model.Workflow
             }
         }
 
-        
+        [JsonIgnore]
         public decimal Total { get
             {
                 return Bill?.Aggregate((decimal)0, (t, l) => t + l.Count * l.UnitaryCost) ?? (decimal)0;
diff --git a/BookAStar/BookAStar/Pages/BookQueryPage.xaml b/BookAStar/BookAStar/Pages/BookQueryPage.xaml
index 1ebee157..d8c19a23 100644
--- a/BookAStar/BookAStar/Pages/BookQueryPage.xaml
+++ b/BookAStar/BookAStar/Pages/BookQueryPage.xaml
@@ -27,7 +27,8 @@
     </StackLayout>
     <StackLayout Orientation="Vertical"  HorizontalOptions="FillAndExpand" VerticalOptions="FillAndExpand" >
     <maps:Map x:Name="map" VerticalOptions="FillAndExpand"></maps:Map>
-    <Button Text="Faire un devis" Clicked="MakeAnEstimate"  VerticalOptions="End" />
+    
+    <Button Text="{Binding EditEstimateButtonText}" Clicked="OnEditEstimate" />
     </StackLayout>
   </StackLayout>
 </ContentPage>
\ No newline at end of file
diff --git a/BookAStar/BookAStar/Pages/BookQueryPage.xaml.cs b/BookAStar/BookAStar/Pages/BookQueryPage.xaml.cs
index 5632ecc9..f547338c 100644
--- a/BookAStar/BookAStar/Pages/BookQueryPage.xaml.cs
+++ b/BookAStar/BookAStar/Pages/BookQueryPage.xaml.cs
@@ -16,11 +16,7 @@ namespace BookAStar.Pages
         {
             get
             {
-                return BindingContext as BookQueryData;
-            }
-            set
-            {
-                BindingContext = value;
+                return (BindingContext as BookQueryViewModel).Data;
             }
         }
         protected override void OnBindingContextChanged()
@@ -55,24 +51,29 @@ namespace BookAStar.Pages
             InitializeComponent();
 
             // Task.Run( async () => { bookQuery = await App.CurrentApp.DataManager.BookQueries.Get(bookQueryId); });
-            
-            BookQuery = bookQuery;
-            
+
+            BindingContext = new BookQueryViewModel(bookQuery);
         }
 
-        private void MakeAnEstimate(object sender, EventArgs ev)
+        private void OnEditEstimate(object sender, EventArgs ev)
         {
-            DataManager.Current.Contacts.Merge(BookQuery.Client);
-            var e = new Estimate()
+            var viewModel = ((BookQueryViewModel)BindingContext).DraftEstimate;
+            if (viewModel == null)
             {
-                ClientId = BookQuery.Client.UserId,
-                CommandId = BookQuery.Id,
-                OwnerId = MainSettings.CurrentUser.Id,
-                Id = 0,
-                Description = "# **Hello Estimate!**"
-            };
+                DataManager.Current.Contacts.Merge(BookQuery.Client);
+                var e = new Estimate()
+                {
+                    ClientId = BookQuery.Client.UserId,
+                    CommandId = BookQuery.Id,
+                    OwnerId = MainSettings.CurrentUser.Id,
+                    Id = 0,
+                    Description = "# **Hello Estimate!**"
+                };
+                viewModel = new EditEstimateViewModel(e, LocalState.New);
+                DataManager.Current.EstimationCache.Add(viewModel);
+            }
             App.NavigationService.NavigateTo<EditEstimatePage>(true,
-                new EditEstimateViewModel(e));
+             viewModel);
         }
 
         protected override void OnSizeAllocated(double width, double height)
diff --git a/BookAStar/BookAStar/Pages/DashboardPage.xaml b/BookAStar/BookAStar/Pages/DashboardPage.xaml
index 4a7b86df..a86f9f59 100644
--- a/BookAStar/BookAStar/Pages/DashboardPage.xaml
+++ b/BookAStar/BookAStar/Pages/DashboardPage.xaml
@@ -21,10 +21,15 @@
   <ScrollView>
     <StackLayout Orientation="Vertical" >
       <StackLayout>
-        <StackLayout>
+        <lc:GesturesContentView ExcludeChildren="false" VisualElement.HeightRequest="{StaticResource BigUserAvatarSize}">
+            <StackLayout>
+          <Label Text="{Binding UserName}" Style="{StaticResource LabelPageHeadingStyle}"
+                                             HorizontalTextAlignment="Center"
+                                             LineBreakMode="WordWrap" XAlign="Center"
+           ></Label>
+          
           <Frame VisualElement.HeightRequest="{StaticResource BigUserAvatarSize}">
-            <lc:GesturesContentView ExcludeChildren="false" VisualElement.HeightRequest="{StaticResource BigUserAvatarSize}">
-
+              
               <lb:Gestures.Interests>
                 <lb:GestureCollection>
                   <lb:GestureInterest GestureType="LongPress"
@@ -35,15 +40,13 @@
               <Image Source="{Binding Avatar}" Aspect="AspectFit"
                      VisualElement.HeightRequest="{StaticResource BigUserAvatarSize}" />
 
-            </lc:GesturesContentView>
+            
           </Frame>
         </StackLayout>
+        </lc:GesturesContentView>
         <views:RatingView Rating="{Binding Rating, Mode=TwoWay}" x:Name="ratingView"/>
 
-        <Label Text="{Binding UserName}" Style="{StaticResource LabelPageHeadingStyle}"
-                               HorizontalTextAlignment="Center"
-                               LineBreakMode="WordWrap" XAlign="Center"
-           ></Label>
+        
       </StackLayout>
 
       <Button Text="{Binding PerformerStatus}" Clicked="OnViewPerformerStatus" />
diff --git a/BookAStar/BookAStar/Pages/EditBillingLinePage.xaml.cs b/BookAStar/BookAStar/Pages/EditBillingLinePage.xaml.cs
index c395d808..863add5f 100644
--- a/BookAStar/BookAStar/Pages/EditBillingLinePage.xaml.cs
+++ b/BookAStar/BookAStar/Pages/EditBillingLinePage.xaml.cs
@@ -1,4 +1,5 @@
-using BookAStar.ViewModels;
+using BookAStar.Data;
+using BookAStar.ViewModels;
 using System;
 using System.Collections.Generic;
 using Xamarin.Forms;
@@ -18,7 +19,6 @@ namespace BookAStar.Pages
         
         public void OnValidateClicked (object sender, EventArgs e)
         {
-
             this.Navigation.PopAsync();
         }
     }
diff --git a/BookAStar/BookAStar/Pages/EditEstimatePage.xaml b/BookAStar/BookAStar/Pages/EditEstimatePage.xaml
index 71623379..a3c5be6e 100644
--- a/BookAStar/BookAStar/Pages/EditEstimatePage.xaml
+++ b/BookAStar/BookAStar/Pages/EditEstimatePage.xaml
@@ -31,13 +31,12 @@
         <Label Grid.Row="0" Grid.Column="1" Text="{Binding Query.Location.Address}" ></Label>
         <Label Grid.Row="0" Grid.Column="2" Text="{Binding Query.EventDate, StringFormat='{0:dddd d MMMM yyyy à hh:mm}'}" ></Label>
       </Grid>
-
+      <Entry Placeholder="Saisissez un titre pour ce devis" Text="{Binding Title, Mode=TwoWay}" />
       <views:MarkdownView x:Name="mdview"
                           Editable="True"
                           HorizontalOptions="FillAndExpand"
       Markdown="{Binding Description, Mode=TwoWay}"
-                          VerticalOptions="Start"
-                        />
+        VerticalOptions="Start" />
 <StackLayout x:Name="biAnVaLayout">
       <ListView x:Name="BillListView" ItemsSource="{Binding Bill}"
          MinimumHeightRequest="40" HasUnevenRows="true" VerticalOptions="FillAndExpand"
diff --git a/BookAStar/BookAStar/Pages/EditEstimatePage.xaml.cs b/BookAStar/BookAStar/Pages/EditEstimatePage.xaml.cs
index ab5c3f1a..a1227f77 100644
--- a/BookAStar/BookAStar/Pages/EditEstimatePage.xaml.cs
+++ b/BookAStar/BookAStar/Pages/EditEstimatePage.xaml.cs
@@ -3,6 +3,7 @@ using Xamarin.Forms;
 
 namespace BookAStar.Pages
 {
+    using Data;
     using Model.Workflow;
     using ViewModels;
     public partial class EditEstimatePage : ContentPage
@@ -13,6 +14,16 @@ namespace BookAStar.Pages
             InitializeComponent();
             BindingContext = model;
         }
+        protected override void OnBindingContextChanged()
+        {
+            base.OnBindingContextChanged();
+            ((EditEstimateViewModel)BindingContext).PropertyChanged += EditEstimatePage_PropertyChanged;
+        }
+
+        private void EditEstimatePage_PropertyChanged(object sender, System.ComponentModel.PropertyChangedEventArgs e)
+        {
+            DataManager.Current.EstimationCache.SaveCollection();
+        }
 
         protected override void OnSizeAllocated(double width, double height)
         {
@@ -37,7 +48,7 @@ namespace BookAStar.Pages
                     Add(com);
                 })
             };
-
+            
             App.NavigationService.NavigateTo<EditBillingLinePage>(
                 true,
                 new object[] { lineView } );
@@ -45,7 +56,16 @@ namespace BookAStar.Pages
 
         protected void OnEstimateValidated(object sender, EventArgs e)
         {
-            throw new NotImplementedException();
+            var evm = (EditEstimateViewModel)BindingContext;
+            if (evm.State == LocalState.New)
+            {
+                DataManager.Current.Estimates.Create(evm.Data);
+                // we have to manually add this item in our local collection,
+                // since we could prefer to update the whole collection
+                // from server, or whatever other scenario
+                DataManager.Current.Estimates.Add(evm.Data);
+                evm.State = LocalState.UpToDate;
+            }
         }
     }
 }
diff --git a/BookAStar/BookAStar/ViewModels/BillingLineViewModel.cs b/BookAStar/BookAStar/ViewModels/BillingLineViewModel.cs
index 01f8ee1f..0ff1d92f 100644
--- a/BookAStar/BookAStar/ViewModels/BillingLineViewModel.cs
+++ b/BookAStar/BookAStar/ViewModels/BillingLineViewModel.cs
@@ -9,7 +9,7 @@ using XLabs.Forms.Mvvm;
 
 namespace BookAStar.ViewModels
 {
-    public class BillingLineViewModel : ViewModel, IBillingLine
+    public class BillingLineViewModel : EditingViewModel, IBillingLine
     {
         BillingLine data;
 
diff --git a/BookAStar/BookAStar/ViewModels/BookQueryViewModel.cs b/BookAStar/BookAStar/ViewModels/BookQueryViewModel.cs
index d59f904f..0c1a5ff6 100644
--- a/BookAStar/BookAStar/ViewModels/BookQueryViewModel.cs
+++ b/BookAStar/BookAStar/ViewModels/BookQueryViewModel.cs
@@ -1,4 +1,5 @@
-using BookAStar.Interfaces;
+using BookAStar.Data;
+using BookAStar.Interfaces;
 using BookAStar.Model;
 using BookAStar.Model.Social;
 using System;
@@ -23,11 +24,34 @@ namespace BookAStar.ViewModels
             Location = data.Location;
             EventDate = data.EventDate;
             Previsionnal = data.Previsionnal;
+            Id = data.Id;
+            this.data = data;
+        }
+        private BookQueryData data;
+        public BookQueryData Data {
+            get
+            {
+                return data;
+            }
         }
         public ClientProviderInfo Client { get; set; }
         public Location Location { get; set; }
         public long Id { get; set; }
         public DateTime EventDate { get; set; }
         public decimal? Previsionnal { get; set; }
+        public EditEstimateViewModel DraftEstimate
+        {
+            get
+            {
+                return DataManager.Current.EstimationCache.LocalGet(this.Id);
+            }
+        }
+        public string EditEstimateButtonText
+        {
+            get
+            {
+                return DraftEstimate != null ? "Editer le devis" : "Faire un devis" ;
+            }
+        }
     }
 }
diff --git a/BookAStar/BookAStar/ViewModels/EditEstimateViewModel.cs b/BookAStar/BookAStar/ViewModels/EditEstimateViewModel.cs
index 64961538..d639b78c 100644
--- a/BookAStar/BookAStar/ViewModels/EditEstimateViewModel.cs
+++ b/BookAStar/BookAStar/ViewModels/EditEstimateViewModel.cs
@@ -1,24 +1,32 @@
 using System.Collections.Generic;
-using XLabs.Forms.Mvvm;
 using BookAStar.Model.Workflow;
 using System.Collections.ObjectModel;
 using BookAStar.Model;
 using Xamarin.Forms;
+using BookAStar.Data;
+using Newtonsoft.Json;
 
 namespace BookAStar.ViewModels
 {
-    public class EditEstimateViewModel : ViewModel
+    public class EditEstimateViewModel : EditingViewModel
     {
-        public EditEstimateViewModel(Estimate data)
+        /// <summary>
+        /// For deserialization
+        /// </summary>
+        public EditEstimateViewModel()
+        {
+
+        }
+        /// <summary>
+        /// Builds a new view model on estimate,
+        /// sets <c>Data</c> with given value parameter
+        /// </summary>
+        /// <param name="data"></param>
+        /// <param name="localState"></param>
+        public EditEstimateViewModel(Estimate data, LocalState localState )
         {
             Data = data;
-            if (data.AttachedFiles == null) data.AttachedFiles = new List<string>();
-            if (data.AttachedGraphics == null) data.AttachedGraphics = new List<string>();
-            if (data.Bill == null) data.Bill = new List<BillingLine>();
-            AttachedFiles = new ObservableCollection<string>(data.AttachedFiles);
-            AttachedGraphicList = new ObservableCollection<string>(data.AttachedGraphics);
-            Bill = new ObservableCollection<BillingLine>(data.Bill);
-            Bill.CollectionChanged += Bill_CollectionChanged;
+            State = localState;
         }
 
         private void Bill_CollectionChanged(object sender, System.Collections.Specialized.NotifyCollectionChangedEventArgs e)
@@ -26,19 +34,31 @@ namespace BookAStar.ViewModels
             Data.Bill = Bill;
             NotifyPropertyChanged("FormattedTotal");
         }
-
-        public Estimate Data { get; protected set; }
-
+        private Estimate data;
+        public Estimate Data { get { return data; } set {
+                data = value;
+                if (data.AttachedFiles == null) data.AttachedFiles = new List<string>();
+                if (data.AttachedGraphics == null) data.AttachedGraphics = new List<string>();
+                if (data.Bill == null) data.Bill = new List<BillingLine>();
+                AttachedFiles = new ObservableCollection<string>(data.AttachedFiles);
+                AttachedGraphicList = new ObservableCollection<string>(data.AttachedGraphics);
+                Bill = new ObservableCollection<BillingLine>(data.Bill);
+                Bill.CollectionChanged += Bill_CollectionChanged;
+            } }
+
+        [JsonIgnore]
         public ObservableCollection<string> AttachedFiles
         {
             get; protected set;
         }
 
+        [JsonIgnore]
         public ObservableCollection<string> AttachedGraphicList
         {
             get; protected set;
         }
 
+        [JsonIgnore]
         public ObservableCollection<BillingLine> Bill
         {
             get; protected set;
@@ -46,6 +66,7 @@ namespace BookAStar.ViewModels
 
 
         string newDesc;
+        [JsonIgnore]
         public string Description
         {
             get
@@ -61,6 +82,7 @@ namespace BookAStar.ViewModels
         }
 
         private int? status;
+        [JsonIgnore]
         public int? Status
         {
             get
@@ -75,6 +97,7 @@ namespace BookAStar.ViewModels
             }
         }
         private string title;
+        [JsonIgnore]
         public string Title
         {
             get
@@ -89,10 +112,13 @@ namespace BookAStar.ViewModels
             }
         }
 
+        [JsonIgnore]
         public ClientProviderInfo Client {  get { return Data.Client; } }
 
+        [JsonIgnore]
         public BookQueryData Query { get { return Data.Query; } }
 
+        [JsonIgnore]
         public FormattedString FormattedTotal
         {
             get
diff --git a/BookAStar/BookAStar/ViewModels/EditingViewModel.cs b/BookAStar/BookAStar/ViewModels/EditingViewModel.cs
new file mode 100644
index 00000000..52aef5f4
--- /dev/null
+++ b/BookAStar/BookAStar/ViewModels/EditingViewModel.cs
@@ -0,0 +1,29 @@
+using BookAStar.Data;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using XLabs.Forms.Mvvm;
+
+namespace BookAStar.ViewModels
+{
+    /// <summary>
+    /// Used to make the DataManager know how
+    /// to sync local and remote data
+    /// </summary>
+    public class EditingViewModel: ViewModel
+    {
+        private LocalState state;
+        public LocalState State {
+            get
+            {
+                return state;
+            }
+            set
+            {
+                base.SetProperty<LocalState>(ref state, value);
+            }
+        } 
+    }
+}
diff --git a/BookAStar/BookAStar/Views/MarkdownView.cs b/BookAStar/BookAStar/Views/MarkdownView.cs
index 543b721e..6f9c8f2b 100644
--- a/BookAStar/BookAStar/Views/MarkdownView.cs
+++ b/BookAStar/BookAStar/Views/MarkdownView.cs
@@ -33,12 +33,11 @@ namespace BookAStar.Views
                     if (Modified != null)
                     {
                         Modified.Invoke(this, new EventArgs());
-                        return;
                     }
                 }
             }
         }
-        private bool editable;
+
         public bool Editable
         {
             get {