When set Expander
direction an error message is displayed
System.InvalidOperationException: 'Header not initialized'
<xct:Expander Direction="Left">
<xct:Expander.Header>
<Label Text="H" TextColor="Black"/>
</xct:Expander.Header>
<StackLayout Orientation="Horizontal" >
<Label Text="!" TextColor="Black" />
<Label Text="D" TextColor="Red" />
</StackLayout>
</xct:Expander>
The code works fine if there is no direction attribute.
This is a known bug https://github.com/xamarin/XamarinCommunityToolkit/issues/1144 which has been fixed in this pr and will be available on a next release.