Wix custom BA installer WPF Launch App after install completes

Question

I've created a custom installer using a WIX and WPF project. I'm trying to implement launching application after installer finish successfully. When i use Process.Start(AppPath); it does not strart the file from the specified path but uses path from the temporary files. In common cases using

<Variable Name="LaunchTarget" Value="[InstallFolder]\pCloud Drive\pCloud.exe"/>

would result in a button in the Finish page but i'm making my custom UI so this is not working.

Edit Somehow now it is working. I'm using

if (LaunchApp)
{
    ProcessStartInfo exeFile = new ProcessStartInfo(this.AppPath);
    Process.Start(exeFile);
}

///don't call Environment.Exit. The BA is a guest in the process, Bootstrapper.Engine.Quit is how you tell Burn that you're done. Burn will call ExitProcess from there.
WixBootstrapper.BootstrapperDispatcher.InvokeShutdown();