This is an undocumented feature and would be very handy for Notes developers.It's a "formula debugger". You can activiate this by holding down the CTRL+SHIFT keys and going to the menu and selecting File-Tools-Debug LotusScript. To turn it off, just repeat the same steps. You won't see a check mark or any indication of its activation in the menu, But when you go into a database and choose an action that uses formula code, a debugging window will pop up similar to the LotusScript debugger. The top half of the panel displays your formula code with the returned values in the bottom half of the screen. You can step through your code.It's really handy and for debugging formula you don't have to keep creating multiple @Prompts in the code. Also, because these techniques are undocumented, use them at your own risk.