Task <bool> ShowLicenseAcceptanceDialog(IEnumerable <NuGetPackageLicense> licenses)
        {
            var res = new TaskCompletionSource <bool> ();

            IdeApp.RunWhenIdle(() => {
                Xwt.Toolkit.NativeEngine.Invoke(delegate {
                    using (LicenseAcceptanceDialog dialog = CreateLicenseAcceptanceDialog(licenses)) {
                        res.SetResult(dialog.Run(Xwt.MessageDialog.RootWindow));
                    }
                });
            });
            return(res.Task);
        }