You double click on the IR command and that brings up the settings for the TX.

If you uncheck the "Repeat while button is pressed", you can change the default 3 repeats to a lower number (2 or even 1). That should solve the problem. But, you won't be able to hold the button now and scroll thru lists.

If you leave the "Repeat while button is pressed" checked, then just make sure the "Minimum Repeat While Pressed" is at 1. That might help. If not then the above unchecked is going to be the best you can do.