diff --git a/src/AdvancedCalculator/Views/MainView.axaml b/src/AdvancedCalculator/Views/MainView.axaml
index 04573d9..197cb81 100644
--- a/src/AdvancedCalculator/Views/MainView.axaml
+++ b/src/AdvancedCalculator/Views/MainView.axaml
@@ -36,7 +36,7 @@
 								<Button x:DataType="vm:MainViewModel"
 										DataContext="{Binding #Root.DataContext}"
 										Command="{Binding InsertVariableCommand}"
-										CommandParameter="{Binding $parent[ListBoxItem].DataContext}"
+                                            CommandParameter="{Binding $parent[ListBoxItem].DataContext.FunctionName}"
 										Background="Transparent" BorderThickness="0" Padding="8" MinHeight="44"
 										AutomationProperties.Name="Insert variable">
 									<Grid ColumnDefinitions="Auto,*,Auto"