To reproduce: - Add button to a split panel - Set button Text property to "Button &X" - Add a event handler for the button - Start the application and press the "x" key To work around this issue instead of using mnemonics you can set shortcuts like this: radButton.ButtonElement.Shortcuts.Add(new RadShortcut(Keys.Alt, Keys.X)); Also you can set mnemonic like underline like this: radButton.Text = "<html>Button <u>X";