Module1.cs

    internal class Module1 : Module
    {
        private static Module1 _this = null;

        /// <summary>
        /// Retrieve the singleton instance to this module here
        /// </summary>
        public static Module1 Current => _this ??= (Module1)FrameworkApplication.FindModule("Addin_Module");

        #region Overrides
        /// <summary>
        /// Called by Framework when ArcGIS Pro is closing
        /// </summary>
        /// <returns>False to prevent Pro from closing, otherwise True</returns>
        protected override bool CanUnload()
        {
            //TODO - add your business logic
            //return false to ~cancel~ Application close
            return true;
        }

        /// <summary>
        /// Called by the Framework either explicitly with FrameworkApplication.FindModule or implicitly whenever any of their DAML elements (Panes, DockPanes, Controls, etc) are loaded.
        /// </summary>
        /// <returns>True if initialization was successful. False if it failed.</returns>
        protected override bool Initialize()
        {
            // subscribe to application events
            EditCompletedEvent.Subscribe(async (x) => {

                Task.Factory.StartNew(() => {
                  var window = new MyProWindow1();
                  window.ShowDialog();
                }, 
                CancellationToken.None, 
                TaskCreationOptions.None, 
                QueuedTask.UIScheduler);
            });

            return base.Initialize();
        }

        #endregion Overrides

    }