Unity 6.1
Render Pipeline: URP
I created a fresh Unity project, installed Noesis and the HelloWorld sample. Then modified the sample XAML to remove most of it and have a combobox. Works fine in Unity editor in the simulator and such. When I deploy it to an Android phone (Samsung Galaxy S9) the combobox doesn't expand and there's no way to select anything in it.

XAML Example Used

<UserControl x:Class="HelloWorld.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" mc:Ignorable="d"
    xmlns:local="clr-namespace:HelloWorld"
    FontFamily="./#Aero Matics"
    FontSize="36"
    Background="#FF124C7A">

    <Grid>
            <Grid Margin="24">
                <Grid HorizontalAlignment="Center">
                    <Grid.ColumnDefinitions>
                        <ColumnDefinition Width="Auto"/>
                        <ColumnDefinition Width="Auto"/>
                    </Grid.ColumnDefinitions>
                    <Grid.RowDefinitions>
                        <RowDefinition/>
                        <RowDefinition/>
                    </Grid.RowDefinitions>

                    <StackPanel x:Name="HelloWorld" Grid.Row="1" Grid.ColumnSpan="2" Margin="0,15,0,0" HorizontalAlignment="Center">
                        <ComboBox x:Name="LanguageSelector" Width="120" Margin="20,0,0,0" VerticalAlignment="Center" HorizontalAlignment="Left">
                            <ComboBoxItem Content="English"/>
                            <ComboBoxItem Content="Spanish"/>
                            <ComboBoxItem Content="French"/>
                        </ComboBox>
                    </StackPanel>
                </Grid>
            </Grid>
    </Grid>
</UserControl>