Thank you for the valuable feedback.
I’ll have this forwarded to UXAccordion development team to be investigated further. I’ll keep you updated with any news I heard from the team regarding this.

#Edited# Reason: adding information about test result

I created a very simple page of UXAccordion and configure the ItemContainerStyle and OptionContainerStyle based on your snippet code. The snippet code of the page is shown below.

<Intersoft:UXPage.Resources>
    <Style x:Key="UXOptionStyle" TargetType="Intersoft:UXAccordionOption">
        <Setter Property="HorizontalContentAlignment" Value="Center"/>
    </Style>
    <Style x:Key="UXItemStyle" TargetType="Intersoft:UXAccordionItem">
        <Setter Property="HorizontalContentAlignment" Value="Right"/>
    </Style>
</Intersoft:UXPage.Resources>

<Intersoft:UXAccordion HorizontalAlignment="Center" VerticalAlignment="Center"
                        Width="150" Height="200"
                        ItemContainerStyle="{StaticResource UXItemStyle}"
                        OptionContainerStyle="{StaticResource UXOptionStyle}">
    <Intersoft:UXAccordionItem Header="Co-Workers">
        <Intersoft:UXAccordionOption Content="Anton"/>
        <Intersoft:UXAccordionOption Content="Brad"/>
        <Intersoft:UXAccordionOption Content="David"/>
        <Intersoft:UXAccordionOption Content="Duke"/>
        <Intersoft:UXAccordionOption Content="Lisa"/>
    </Intersoft:UXAccordionItem>
    <Intersoft:UXAccordionItem Header="Friends">
        <Intersoft:UXAccordionOption Content="Jane"/>
        <Intersoft:UXAccordionOption Content="John"/>
        <Intersoft:UXAccordionOption Content="Luke"/>
    </Intersoft:UXAccordionItem>
    <Intersoft:UXAccordionItem Header="Family">
        <Intersoft:UXAccordionOption Content="Adam"/>
        <Intersoft:UXAccordionOption Content="Anna"/>
        <Intersoft:UXAccordionOption Content="Eden"/>
        <Intersoft:UXAccordionOption Content="Eva"/>
    </Intersoft:UXAccordionItem>
</Intersoft:UXAccordion>

Please note that in my sample, the ItemContainerStyle is assigned to UXItemStyle and the OptionContainerStyle is assigned to UXContainerStyle.

Following is the screenshot of how the UXAccordion rendered in browser.

I enclosed the xaml page as attachment. Please kindly test the page and let us know if you have different result.

Yes your test project works. The problem is on DataBinding, i attach a project. Run the proect and see the error showed.

regards.

This specific problem only happens on WPF environment.

In order to address this issue, please try to modify the UXPage1.xaml file into the following. Please note that in the modified version, UXAccordion.ItemTemplate is added as the option template.

<Intersoft:UXAccordion HorizontalAlignment="Center" VerticalAlignment="Center"
                        Width="150" Height="200" ItemsSource="{Binding Items}"
                        SelectionMode="One" ItemContainerStyle="{StaticResource UXItemStyle}">
    <Intersoft:UXAccordion.ItemTemplate>
        <HierarchicalDataTemplate ItemContainerStyle="{StaticResource UXOptionStyle}"
                                    ItemsSource="{Binding Options}">
            <TextBlock Text="{Binding Nombre}"/>
        </HierarchicalDataTemplate>
    </Intersoft:UXAccordion.ItemTemplate>
</Intersoft:UXAccordion>

I will inform you any news I heard from the team regarding this.