diff --git a/src/Avalonia.Themes.Default/DefaultTheme.xaml b/src/Avalonia.Themes.Default/DefaultTheme.xaml
index 97cff5d94b..4e63d1d223 100644
--- a/src/Avalonia.Themes.Default/DefaultTheme.xaml
+++ b/src/Avalonia.Themes.Default/DefaultTheme.xaml
@@ -37,6 +37,7 @@
   <StyleInclude Source="resm:Avalonia.Themes.Default.TextBox.xaml?assembly=Avalonia.Themes.Default"/>
   <StyleInclude Source="resm:Avalonia.Themes.Default.ToggleButton.xaml?assembly=Avalonia.Themes.Default"/>
   <StyleInclude Source="resm:Avalonia.Themes.Default.Expander.xaml?assembly=Avalonia.Themes.Default"/>
+  <StyleInclude Source="resm:Avalonia.Themes.Default.TitleBar.xaml?assembly=Avalonia.Themes.Default"/>
   <StyleInclude Source="resm:Avalonia.Themes.Default.TreeView.xaml?assembly=Avalonia.Themes.Default"/>
   <StyleInclude Source="resm:Avalonia.Themes.Default.TreeViewItem.xaml?assembly=Avalonia.Themes.Default"/>
   <StyleInclude Source="resm:Avalonia.Themes.Default.UserControl.xaml?assembly=Avalonia.Themes.Default"/>