WPF with touchscreen, listbox opens a modal window doesn't respond

Question

I'm facing a problem since some weeks/months, i hope someone can help me ;) This WPF problem appears only when using via the touch screen, it works fine with mouse. The concept to reproduce is very simple: - 1 window with a listbox or listview - You populate the list with simple item (just a text for example) - A second window with 2 or more simple buttons

When you select an item in the list in window 1 via touch screen, it opens in modal mode (ShowDialog) the second window. When the second window is open you can't touch any button at first touch! If you do the same with the mouse it is working fine! It looks like the touch event is not finished when you call the window 2 ShowDialog (it works fine when it is not modal: using Show).

Here the XAML window 1:

<Window x:Class="MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="MainWindow" Height="500" Width="661" WindowStartupLocation="CenterScreen">
    <StackPanel>
        <ListView x:Name="lstItems" Height="300" Margin="10,10,20,10" Width="Auto" ItemsSource="{Binding}" BorderBrush="{x:Null}"
                         SelectionMode="Single"  Visibility="Visible" ScrollViewer.VerticalScrollBarVisibility="Hidden">
        </ListView>
    </StackPanel>
</Window>

Here the code behind for window 1:

Class MainWindow
    Private Sub MainWindow_Loaded(sender As Object, e As RoutedEventArgs) Handles Me.Loaded
        With lstItems
            .Items.Clear()
            For i = 0 To 50
                .Items.Add("test #" & i.ToString)
            Next
        End With
    End Sub

    Private Sub lstItems_SelectionChanged(sender As Object, e As SelectionChangedEventArgs) Handles lstItems.SelectionChanged
        Dim _frm As frm2 = New frm2
        _frm.ClickedItem = lstItems.SelectedItem.ToString
        _frm.ShowDialog()
        _frm.Close()
        _frm = Nothing
    End Sub

End Class

Here the window 2 xaml:

<Window x:Class="frm2"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="frm2" Height="393" Width="661" WindowStartupLocation="CenterScreen">
    <Grid>
        <UniformGrid Columns="2">
            <Button x:Name="cmdbutton1" Height="128" Content="Button1"/>
            <Button x:Name="cmdbutton2" Height="128" Content="Button2"/>
        </UniformGrid>
    </Grid>
</Window>

Here the code behind for window 2:

Public Class frm2
    Property ClickedItem As String = ""

    Private Sub frm2_Loaded(sender As Object, e As RoutedEventArgs) Handles Me.Loaded
        Me.Title = ClickedItem
    End Sub

    Private Sub cmdbutton1_Click(sender As Object, e As RoutedEventArgs) Handles cmdbutton1.Click
        Me.Close()
    End Sub

    Private Sub cmdbutton2_Click(sender As Object, e As RoutedEventArgs) Handles cmdbutton2.Click
        Me.Close()
    End Sub
End Class

Thank you in advance for your help...

Answer 1

Solution is here, you have just declare your sub in Async and do a task wait...

      Private Async Sub lstItems_SelectionChanged(sender As Object, e As SelectionChangedEventArgs) Handles lstItems.SelectionChanged

Await Task.Delay(1)

    Dim _frm As frm2 = New frm2
    _frm.ClickedItem = lstItems.SelectedItem.ToString
    _frm.ShowDialog()
    _frm.Close()
    _frm = Nothing