The On-Line Operations manual for Note Expression says:
“When working with Note Expression, start by activating the “Show Note Expression Data” button on the Key Editor toolbar. This will give you a visual feedback of your actions. Use the slider to the right of the button to modify the display size of the Note Expression data in the event display.”
Below that is a screen clip showing the Step Input button.. 
Here’s a screen shot showing the correct control, which a user may not have enabled in set-up. Note, in this example, I moved the Step Input button next to the Note Expression Display button.
