Question

I grabbed the entire template for a combobox to make some modifications. The style for ComboBoxItem is this:

    <Style x:Key="ComboBoxItemStyle" TargetType="{x:Type ComboBoxItem}">
        <Setter Property="OverridesDefaultStyle" Value="True"></Setter>
        <Setter Property="Background" Value="{DynamicResource StandardBlackBrush}"></Setter>
        <Setter Property="FocusVisualStyle" Value="{x:Null}"></Setter>
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="{x:Type ComboBoxItem}">
                    <Border x:Name="Bd" BorderBrush="{DynamicResource StandardBlackBrush}" BorderThickness="3" SnapsToDevicePixels="true" >
                        <ContentPresenter x:Name="Cp" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" VerticalAlignment="{TemplateBinding VerticalContentAlignment}"/>
                    </Border>       
                    <ControlTemplate.Triggers>
                        <Trigger Property="IsHighlighted" Value="true">
                            <Setter TargetName="Bd" Property="BorderBrush" Value="{DynamicResource StandardFocusRectangleBrush}"/>
                        </Trigger>
                    </ControlTemplate.Triggers>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style >             

This results in very small combo box items that are just the height/width of the content, which is just a text string. To make these items bigger, I add a margin to the ContentPresenter and it looks fine:

<ContentPresenter Margin="20,10,20,10" x:Name="Cp" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" VerticalAlignment="{TemplateBinding VerticalContentAlignment}"/>

But, then mouse clicks still have to be within the text area. Mouse clicks outside of the text but within the border close the popup but do not make a selection. This is my problem.

Answer 1

This happens because the border wont react to mouse clicks when it has no background set.

So to fix your problem, you set the following on the border element in XAML:

Background="Transparent"