diff --git a/src/AdvancedCalculator/Views/MainView.axaml b/src/AdvancedCalculator/Views/MainView.axaml
index 197cb81..266eb68 100644
--- a/src/AdvancedCalculator/Views/MainView.axaml
+++ b/src/AdvancedCalculator/Views/MainView.axaml
@@ -120,7 +120,7 @@
 													<Button x:DataType="vm:MainViewModel"
 															DataContext="{Binding #Root.DataContext}"
 															Command="{Binding InsertFunctionCommand}"
-															CommandParameter="{Binding $parent[ListBoxItem].DataContext}"
+                            CommandParameter="{Binding $parent[ListBoxItem].DataContext.VariableName}"
 															Background="Transparent" BorderThickness="0" Padding="8" MinHeight="44"
 															AutomationProperties.Name="Insert function">
 														<StackPanel Spacing="8"