Suppose you were lucky to find this article and already resolved all your compile time errors. I found an issue that may require redesign of your application, even though everything else appears to be working fine. I’ll put it straight: MenuStrip/ToolStripMenuItem pair is not 100% backwards compatible with MainMenu/MenuItem. One particular thing is how keyboard shortcuts work. In MainMenu concept, triggering a shortcut by pressing a hotkey combination causes .NET framework to open the corresponding menu under the hood, process Popup event and only then click the MenuItem.