diff --git a/src/AdvancedCalculator/Views/MainView.axaml b/src/AdvancedCalculator/Views/MainView.axaml
index 927f01a..f82f6a1 100644
--- a/src/AdvancedCalculator/Views/MainView.axaml
+++ b/src/AdvancedCalculator/Views/MainView.axaml
@@ -7,7 +7,8 @@
              xmlns:conv="clr-namespace:AdvancedCalculator.Converters"
              mc:Ignorable="d" d:DesignWidth="900" d:DesignHeight="600"
              x:Class="AdvancedCalculator.Views.MainView"
-             x:DataType="vm:MainViewModel">
+             x:DataType="vm:MainViewModel"
+             x:Name="Root">
   <UserControl.Resources>
     <conv:BoolToGridLengthConverter x:Key="BoolToGridLengthConverter" />
     <conv:WidthToBooleanConverter x:Key="WidthToBooleanConverter" />
@@ -35,15 +36,12 @@
           <ListBox ItemsSource="{Binding Variables}" SelectedIndex="-1"
                    AutomationProperties.Name="Variables list">
             <ListBox.ItemTemplate>
-              <DataTemplate>
+              <DataTemplate x:DataType="m:VariableItem">
                 <Button Background="Transparent" BorderThickness="0" Padding="8" MinHeight="44"
                         AutomationProperties.Name="Insert variable"
-                        Tag="{Binding}"
-                        DataContext="{Binding $parent[UserControl].DataContext}"
-                        Command="{Binding InsertVariableCommand}"
-                        CommandParameter="{Binding Tag.VariableName, RelativeSource={RelativeSource Self}}">
+                        Command="{Binding DataContext.InsertVariableCommand, ElementName=Root}"
+                        CommandParameter="{Binding VariableName}">
                   <Grid ColumnDefinitions="Auto,*,Auto"
-                        DataContext="{Binding Tag, RelativeSource={RelativeSource AncestorType=Button}}"
                         x:DataType="m:VariableItem">
                     <TextBlock Grid.Column="0" FontFamily="{StaticResource MDI}"
                                FontSize="{DynamicResource IconSizeM}" Text="{Binding Icon}" VerticalAlignment="Center" Margin="0,0,8,0" />
@@ -69,15 +67,12 @@
                  ItemsSource="{x:Static m:FunctionDefinitionItem.DefinedFunctions}"
                  AutomationProperties.Name="Functions list">
             <ListBox.ItemTemplate>
-              <DataTemplate>
+              <DataTemplate x:DataType="m:FunctionDefinitionItem">
                 <Button Background="Transparent" BorderThickness="0" Padding="8" MinHeight="44"
                         AutomationProperties.Name="Insert function"
-                        Tag="{Binding}"
-                        DataContext="{Binding $parent[UserControl].DataContext}"
-                        Command="{Binding InsertFunctionCommand}"
-                        CommandParameter="{Binding Tag.FunctionName, RelativeSource={RelativeSource Self}}">
+                        Command="{Binding DataContext.InsertFunctionCommand, ElementName=Root}"
+                        CommandParameter="{Binding FunctionName}">
                   <StackPanel Spacing="8"
-                              DataContext="{Binding Tag, RelativeSource={RelativeSource AncestorType=Button}}"
                               x:DataType="m:FunctionDefinitionItem">
                     <StackPanel Orientation="Horizontal" Spacing="8" VerticalAlignment="Center">
                       <TextBlock FontFamily="{StaticResource MDI}" Text="{Binding Icon}" />