To reproduce: Create MDI form using RadDock by following the article: http://www.telerik.com/help/winforms/dock-mdi-mode-automatic-mdi-form-handling.html You will notice that the Closing and Closed events of the MdiForms will not be invoked. Workaround: Subscribe to the FormClosing event of the main Form and close all the windows manually: void Form1_FormClosing(object sender, FormClosingEventArgs e) { this.RadDock.CloseAllWindows(); }