I would like to suggest an improvement to the Show Message behavior. Instead of only “OK or Cancel” or “Yes or No” options, how about a “Yes, No, or Cancel” option?
This would be useful in my current form, which prompts a user on close. After a user clicks close, if they have un-submitted changes, a message asks the user if they would like to submit the changes. Right now, they can click Yes or No. If yes, the changes are submitted and the form is closed. If no, the changes are not submitted, and the form is closed. If there were a cancel option, the user can click cancel and prevent the form from closing.
I can think of several workarounds (such as, if the user clicks no, have a second message ask if they would still like to close the form), but I think having a cancel button would be a cleaner way to achieve the objective.