# Example, GUI app that freezes
[void][System.Reflection.Assembly]::LoadWithPartialName('System.Windows.Forms')
$Form = [System.Windows.Forms.Form] @{
    Text = 'My GUI Window'
}
$ListBox = [System.Windows.Forms.ListBox] @{
    Dock = [System.Windows.Forms.DockStyle]::Fill
}
$Button = [System.Windows.Forms.Button] @{
    Text = 'Do something'
    Dock = [System.Windows.Forms.DockStyle]::Bottom
}
$Button.Add_Click(
    {
        $ListBox.Items.Insert(0, ('{0}: Do something' -f [Datetime]::Now))
        [System.Threading.Thread]::Sleep(5000)
        $ListBox.Items.Insert(0, ('{0}: Do something again' -f [Datetime]::Now))
    }
)
[void] $Form.Controls.AddRange(@($ListBox, $Button))
[void] $Form.ShowDialog()

# Example how to resolve the freeze issue with the same app
$Sync = [HashTable]::Synchronized(@{})
$Sync.Actions = [System.Collections.Queue]::new()
$PowerShell = [PowerShell]::Create()
$PowerShell.Runspace = [RunspaceFactory]::CreateRunspace()
$PowerShell.Runspace.Open()
$PowerShell.Runspace.SessionStateProxy.SetVariable('Sync', $Sync)
# Run the GUI in a separate thread, that we dont freeze on user actions
$Handle = $PowerShell.AddScript(
    {
        [void][System.Reflection.Assembly]::LoadWithPartialName('System.Windows.Forms')
        $Sync.Form = [System.Windows.Forms.Form] @{
            Text = 'My GUI Window'
        }
        $Sync.ListBox = [System.Windows.Forms.ListBox] @{
            Dock = [System.Windows.Forms.DockStyle]::Fill
        }
        $Button = [System.Windows.Forms.Button] @{
            Text = 'Do something'
            Dock = [System.Windows.Forms.DockStyle]::Bottom
        }
        $Button.Add_Click(
            {
                $Sync.Actions.Enqueue('Do something')
            }
        )
        [void] $Sync.Form.Controls.AddRange(@($Sync.ListBox, $Button))
        [void] $Sync.Form.ShowDialog()
    }
).BeginInvoke()

# While the handle of the separate thread we created is still running
While (!$Handle.IsCompleted) {
    While ($Sync.Actions.Count -gt 0) {
        # Manage the actions we queue from inside
        Switch ($Sync.Actions.Dequeue()) {
            'Do something' {
                $Sync.ListBox.Items.Insert(0, ('{0}: Do something' -f [Datetime]::Now))
                [System.Threading.Thread]::Sleep(5000)
                $Sync.ListBox.Items.Insert(0, ('{0}: Do something again' -f [Datetime]::Now))
            }
        }
    }
    [System.Threading.Thread]::Sleep(100)
}