[SplitButton] Incorrect height

[niels9001]

Describe the bug

Compared to other button controls, SplitButton does not seem to have the correct height.

Windows UI Kit (Figma):

Steps to reproduce the bug

 <StackPanel
     HorizontalAlignment="Right"
     VerticalAlignment="Center"
     Orientation="Horizontal">
     <DropDownButton VerticalAlignment="Bottom" Content="DropDownButton" />
     <SplitButton VerticalAlignment="Bottom" Content="SplitButton" />
     <Button VerticalAlignment="Bottom" Content="Button" />
 </StackPanel>

NuGet package version

1.7.250310001

[United600]

This occurs because the control where the padding is applied to the content does not have a border thickness (like the other button controls shown).

microsoft-ui-xaml/dev/SplitButton/SplitButton.xaml

Lines 268 to 288 in 232a16e

	<Button x:Name="PrimaryButton"
	Grid.Column="0"
	Foreground="{TemplateBinding Foreground}"
	Background="{TemplateBinding Background}"
	BorderThickness="0"
	BorderBrush="Transparent"
	Content="{TemplateBinding Content}"
	ContentTransitions="{TemplateBinding ContentTransitions}"
	ContentTemplate="{TemplateBinding ContentTemplate}"
	Command="{TemplateBinding Command}"
	CommandParameter="{TemplateBinding CommandParameter}"
	FontFamily="{TemplateBinding FontFamily}"
	FontSize="{TemplateBinding FontSize}"
	FontWeight="{TemplateBinding FontWeight}"
	HorizontalAlignment="Stretch"
	VerticalAlignment="Stretch"
	HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}"
	VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}"
	Padding="{TemplateBinding Padding}"
	IsTabStop="False"
	AutomationProperties.AccessibilityView="Raw"/>

<Button x:Name="PrimaryButton"
-    BorderThickness="0"
+    BorderThickness="{TemplateBinding BorderThickness}"
/>

PS. WinUI 3 styles are a pain to reference because they lack consistent or "proper" formatting.

[niels9001]

This issue has been fixed in 1.8-stable

[United600]

This issue has been fixed in 1.8-stable

Not fixed, and is easily reproducible by setting the screen scale factor to 150%.

This is not the solution:

microsoft-ui-xaml/src/controls/dev/SplitButton/SplitButton_themeresources.xaml

Line 103 in 61382c0

<Thickness x:Key="SplitButtonPadding">11,6,11,7</Thickness>

The padding should remain as ButtonPadding. The only solution I'm aware of is to set the PrimaryButton BorderThickness.