diff --git a/PacticeSolution/MVVMButtonControl/MainWindow.xaml b/PacticeSolution/MVVMButtonControl/MainWindow.xaml
index 29fe560..6bf334c 100644
--- a/PacticeSolution/MVVMButtonControl/MainWindow.xaml
+++ b/PacticeSolution/MVVMButtonControl/MainWindow.xaml
@@ -12,18 +12,18 @@
     </Window.DataContext>
 
     <StackPanel>
-        <Button Content="Add TextBox" Command="{Binding TestCommand}"/>
-        <ItemsControl x:Name="itcMain" ItemsSource="{Binding ButtonCollection}">
+        <Button x:Name="btnMain" Content="Add TextBox" Command="{Binding TestCommand}"/>
+        <ItemsControl x:Name="ctrMain" ItemsSource="{Binding ButtonCollection}">
             <ItemsControl.ItemTemplate>
                 <DataTemplate>
-                    <Button x:Name="btnItem" 
+                    <Button x:Name="btnSub"
                             Content="{Binding Name, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"
                             FontWeight="Bold"
                             FontSize="18"
                             Margin="10"
                             Width="100"
                             Background="{Binding SelectedColor, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"
-                            Command="{Binding ElementName=itcMain, Path=SubCommandMethod}"
+                            Command="{Binding ElementName=ctrMain, Path=DataContext.SubButtonCommand}"
                             CommandParameter="{Binding Name}"/>
                 </DataTemplate>
             </ItemsControl.ItemTemplate>
diff --git a/PacticeSolution/MVVMButtonControl/ViewModel/ModelViewMain.cs b/PacticeSolution/MVVMButtonControl/ViewModel/ModelViewMain.cs
index 06b51f3..6bc9595 100644
--- a/PacticeSolution/MVVMButtonControl/ViewModel/ModelViewMain.cs
+++ b/PacticeSolution/MVVMButtonControl/ViewModel/ModelViewMain.cs
@@ -52,7 +52,7 @@ namespace MVVMButtonControl.ViewModel
                 this.ButtonCollection[i].SelectedColor = Brushes.Transparent;
             }
 
-            Buttons selected = this.ButtonCollection.Where(b => b.Name.Equals(parameter.ToString())).SingleOrDefault();
+            Buttons? selected = this.ButtonCollection.Where(b => b.Name.Equals(parameter.ToString())).SingleOrDefault();
             if (selected == null)
                 return;