diff --git a/BookAStar/BookAStar/Pages/BookQueryPage.xaml b/BookAStar/BookAStar/Pages/BookQueryPage.xaml
index d8c19a23..11b3d615 100644
--- a/BookAStar/BookAStar/Pages/BookQueryPage.xaml
+++ b/BookAStar/BookAStar/Pages/BookQueryPage.xaml
@@ -26,9 +26,8 @@
     <Label Text="{Binding Previsional}" />
     </StackLayout>
     <StackLayout Orientation="Vertical"  HorizontalOptions="FillAndExpand" VerticalOptions="FillAndExpand" >
-    <maps:Map x:Name="map" VerticalOptions="FillAndExpand"></maps:Map>
-    
-    <Button Text="{Binding EditEstimateButtonText}" Clicked="OnEditEstimate" />
+    <maps:Map x:Name="map" HorizontalOptions="FillAndExpand" VerticalOptions="FillAndExpand"></maps:Map>
+    <Button Text="{Binding EditEstimateButtonText}" Clicked="OnEditEstimate" VerticalOptions="End"/>
     </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 f547338c..57173a3c 100644
--- a/BookAStar/BookAStar/Pages/BookQueryPage.xaml.cs
+++ b/BookAStar/BookAStar/Pages/BookQueryPage.xaml.cs
@@ -7,6 +7,7 @@ namespace BookAStar.Pages
     using Data;
     using Model;
     using Model.Workflow;
+    using System.Linq;
     using ViewModels;
 
     public partial class BookQueryPage : ContentPage
@@ -57,23 +58,35 @@ namespace BookAStar.Pages
 
         private void OnEditEstimate(object sender, EventArgs ev)
         {
-            var viewModel = ((BookQueryViewModel)BindingContext).DraftEstimate;
-            if (viewModel == null)
+            var bookQueryViewModel = (BookQueryViewModel)BindingContext;
+
+            var editEstimateViewModel = bookQueryViewModel.DraftEstimate;
+            if (editEstimateViewModel == null)
             {
-                DataManager.Current.Contacts.Merge(BookQuery.Client);
-                var e = new Estimate()
+                // First search for an existing estimate
+                var estimateToEdit = DataManager.Current.Estimates.FirstOrDefault(
+                    estimate=> estimate.CommandId == bookQueryViewModel.Id
+                    );
+                if (estimateToEdit == null)
                 {
-                    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);
+                    DataManager.Current.Contacts.Merge(BookQuery.Client);
+                    estimateToEdit = new Estimate()
+                    {
+                        ClientId = BookQuery.Client.UserId,
+                        CommandId = BookQuery.Id,
+                        OwnerId = MainSettings.CurrentUser.Id,
+                        Id = 0,
+                        Description = "# **Hello Estimate!**"
+                    };
+                    editEstimateViewModel = new EditEstimateViewModel(estimateToEdit, LocalState.New);
+                }
+                else
+                    editEstimateViewModel = new EditEstimateViewModel(estimateToEdit, LocalState.UpToDate);
+
+                DataManager.Current.EstimationCache.Add(editEstimateViewModel);
             }
             App.NavigationService.NavigateTo<EditEstimatePage>(true,
-             viewModel);
+             editEstimateViewModel);
         }
 
         protected override void OnSizeAllocated(double width, double height)
diff --git a/BookAStar/BookAStar/Pages/EditBillingLinePage.xaml b/BookAStar/BookAStar/Pages/EditBillingLinePage.xaml
index bd66e782..6ce717aa 100644
--- a/BookAStar/BookAStar/Pages/EditBillingLinePage.xaml
+++ b/BookAStar/BookAStar/Pages/EditBillingLinePage.xaml
@@ -93,8 +93,10 @@
                                 Path=IsValid, 
                                 Converter={StaticResource boolToStyleImage}}" />
       </StackLayout>
-
-        <Button Text="Valider cette ligne de devis"
+        <Button Text="Términé"
+                    Command="{Binding DeleteCommand}"
+                    Clicked="OnValidateClicked"></Button>
+        <Button Text="Términé"
                 Command="{Binding ValidateCommand}"
                 Clicked="OnValidateClicked"></Button>
   </StackLayout>
diff --git a/BookAStar/BookAStar/Pages/EditBillingLinePage.xaml.cs b/BookAStar/BookAStar/Pages/EditBillingLinePage.xaml.cs
index 863add5f..779d189e 100644
--- a/BookAStar/BookAStar/Pages/EditBillingLinePage.xaml.cs
+++ b/BookAStar/BookAStar/Pages/EditBillingLinePage.xaml.cs
@@ -21,5 +21,11 @@ namespace BookAStar.Pages
         {
             this.Navigation.PopAsync();
         }
+        protected override bool OnBackButtonPressed()
+        {
+            var bvm = (BillingLineViewModel)BindingContext;
+            bvm.ValidateCommand?.Execute(null);
+            return base.OnBackButtonPressed();
+        }
     }
 }
diff --git a/BookAStar/BookAStar/Pages/EditEstimatePage.xaml b/BookAStar/BookAStar/Pages/EditEstimatePage.xaml
index a3c5be6e..3e4a4bc4 100644
--- a/BookAStar/BookAStar/Pages/EditEstimatePage.xaml
+++ b/BookAStar/BookAStar/Pages/EditEstimatePage.xaml
@@ -40,7 +40,7 @@
 <StackLayout x:Name="biAnVaLayout">
       <ListView x:Name="BillListView" ItemsSource="{Binding Bill}"
          MinimumHeightRequest="40" HasUnevenRows="true" VerticalOptions="FillAndExpand"
-                          HeightRequest="40">
+                          HeightRequest="40" ItemTapped="OnEditLine">
         <ListView.ItemTemplate>
           <DataTemplate >
             <ViewCell>
diff --git a/BookAStar/BookAStar/Pages/EditEstimatePage.xaml.cs b/BookAStar/BookAStar/Pages/EditEstimatePage.xaml.cs
index 3bfdae2b..4c46a728 100644
--- a/BookAStar/BookAStar/Pages/EditEstimatePage.xaml.cs
+++ b/BookAStar/BookAStar/Pages/EditEstimatePage.xaml.cs
@@ -14,6 +14,7 @@ namespace BookAStar.Pages
             InitializeComponent();
             BindingContext = model;
         }
+
         protected override void OnBindingContextChanged()
         {
             base.OnBindingContextChanged();
@@ -41,17 +42,36 @@ namespace BookAStar.Pages
         protected void OnNewCommanLine(object sender, EventArgs e)
         {
             var com = new BillingLine() { Count = 1, UnitaryCost = 0.01m };
-            var lineView = new BillingLineViewModel(com);
-            var bill =
-            ((EditEstimateViewModel)BindingContext).Bill;
-            bill.Add(com);
-            bill.SaveCollection();
-            lineView.PropertyChanged += (s,f) => bill.SaveCollection();
+            var bill = ((EditEstimateViewModel)BindingContext).Bill;
+            var lineView = new BillingLineViewModel(com)
+            { ValidateCommand = new Command(() => {
+                bill.Add(com);
+                bill.SaveCollection();
+            })};
             App.NavigationService.NavigateTo<EditBillingLinePage>(
                 true,
                 new object[] { lineView } );
         }
+        protected void OnEditLine(object sender, ItemTappedEventArgs e)
+        {
+            var line = (BillingLine)e.Item;
+            var bill = ((EditEstimateViewModel)BindingContext).Bill;
+            var lineView = new BillingLineViewModel(line)
+            {
+                ValidateCommand = new Command(() => {
+                    bill.SaveCollection();
+                })
+            };
+            lineView.PropertyChanged += LineView_PropertyChanged;
+            App.NavigationService.NavigateTo<EditBillingLinePage>(
+                true,
+                new object[] { lineView });
+        }
 
+        private void LineView_PropertyChanged(object sender, System.ComponentModel.PropertyChangedEventArgs e)
+        {
+            DataManager.Current.EstimationCache.SaveCollection();
+        }
 
         protected void OnEstimateValidated(object sender, EventArgs e)
         {
@@ -68,7 +88,9 @@ namespace BookAStar.Pages
                 DataManager.Current.Estimates.Update(evm.Data);
             }
             DataManager.Current.Estimates.SaveCollection();
-            evm.State = LocalState.UpToDate;
+            DataManager.Current.EstimationCache.Remove(evm);
+            DataManager.Current.EstimationCache.SaveCollection();
+            Navigation.PopAsync();
         }
     }
 }
diff --git a/BookAStar/BookAStar/ViewModels/BillingLineViewModel.cs b/BookAStar/BookAStar/ViewModels/BillingLineViewModel.cs
index 0ff1d92f..051280bb 100644
--- a/BookAStar/BookAStar/ViewModels/BillingLineViewModel.cs
+++ b/BookAStar/BookAStar/ViewModels/BillingLineViewModel.cs
@@ -13,48 +13,57 @@ namespace BookAStar.ViewModels
     {
         BillingLine data;
 
-        public BillingLineViewModel( BillingLine data)
+        public BillingLineViewModel(BillingLine data)
         {
             this.data = data ?? new BillingLine();
             // sets durationValue & durationUnit
+            count = data.Count;
+            description = data.Description;
+
             Duration = data.Duration;
-            unitaryCostText = data.UnitaryCost.ToString("G",CultureInfo.InvariantCulture);
+            unitaryCostText = data.UnitaryCost.ToString("G", CultureInfo.InvariantCulture);
         }
 
+        private int count;
         public int Count
         {
             get
             {
-                return data.Count;
+                return count;
             }
 
             set
             {
-                data.Count = value;
+                SetProperty<int>(ref count, value);
+                data.Count = count;
             }
         }
+        private string description;
         public string Description
         {
             get
             {
-                return data.Description;
+                return description;
             }
 
             set
             {
-                data.Description = value;
+                SetProperty<string>(ref description, value);
+                data.Description = description;
             }
         }
+        decimal unitaryCost;
         public decimal UnitaryCost
         {
             get
             {
-                return data.UnitaryCost;
+                return unitaryCost;
             }
 
             set
             {
-                data.UnitaryCost = value;
+                SetProperty<decimal>(ref unitaryCost, value);
+                data.UnitaryCost = unitaryCost;
             }
         }
 
@@ -72,12 +81,12 @@ namespace BookAStar.ViewModels
                 data.Duration = this.Duration;
             }
         }
-        
-        public enum DurationUnits:int
+
+        public enum DurationUnits : int
         {
-            Jours=0,
-            Heures=1,
-            Minutes=2
+            Jours = 0,
+            Heures = 1,
+            Minutes = 2
         }
         private DurationUnits durationUnit;
 
@@ -85,17 +94,17 @@ namespace BookAStar.ViewModels
 pour décrire la quantité de travail associée à ce type de service")]
         public DurationUnits DurationUnit
         {
-            get {
+            get
+            {
                 return durationUnit;
             }
             set
             {
-               SetProperty<DurationUnits>(ref durationUnit, value, "DurationUnit");
-               data.Duration = this.Duration;
+                SetProperty<DurationUnits>(ref durationUnit, value, "DurationUnit");
+                data.Duration = this.Duration;
             }
         }
-
-        protected decimal unitaryCost;
+        
         public static readonly string unitCostFormat = "0,.00";
         string unitaryCostText;
         public string UnitaryCostText
@@ -129,7 +138,7 @@ pour décrire la quantité de travail associée à ce type de service")]
                     case DurationUnits.Heures:
                         return new TimeSpan(DurationValue, 0, 0);
                     case DurationUnits.Jours:
-                        return new TimeSpan(DurationValue*24, 0, 0);
+                        return new TimeSpan(DurationValue * 24, 0, 0);
                     case DurationUnits.Minutes:
                         return new TimeSpan(0, DurationValue, 0);
                     // Assert(false); since all units are treated bellow
@@ -143,21 +152,21 @@ pour décrire la quantité de travail associée à ce type de service")]
                 double days = value.TotalDays;
                 if (days >= 1.0)
                 {
-                    DurationValue = (int) days;
+                    DurationValue = (int)days;
                     DurationUnit = DurationUnits.Jours;
                     return;
                 }
                 double hours = value.TotalHours;
                 if (hours >= 1.0)
                 {
-                    DurationValue = (int) hours;
+                    DurationValue = (int)hours;
                     DurationUnit = DurationUnits.Jours;
                     return;
                 }
-                DurationValue = (int) value.TotalMinutes;
+                DurationValue = (int)value.TotalMinutes;
                 DurationUnit = DurationUnits.Minutes;
             }
         }
-        
+
     }
 }