diff --git a/src/MaterialDesignThemes.Wpf/Themes/MaterialDesignTheme.PopupBox.xaml b/src/MaterialDesignThemes.Wpf/Themes/MaterialDesignTheme.PopupBox.xaml
index 5a5fe19a52..c31d7f292a 100644
--- a/src/MaterialDesignThemes.Wpf/Themes/MaterialDesignTheme.PopupBox.xaml
+++ b/src/MaterialDesignThemes.Wpf/Themes/MaterialDesignTheme.PopupBox.xaml
@@ -108,7 +108,7 @@
           </ControlTemplate.Resources>
           <Grid>
             <ToggleButton x:Name="PART_Toggle"
-                          VerticalAlignment="Center"
+                          VerticalAlignment="Stretch"
                           HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}"
                           VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}"
                           Content="{TemplateBinding ToggleContent}"