Staff Text is entered for the user input text (e.g. accel. or rit.) rather than System Text. This requires you to delete the automatically entered text and reenter it as system text. If you don't manually fix it the text will only show up on the selected staff where the tempo change is entered. It should show up above the top staff of a conductors score and every staff on the parts so the piccolo player is not the only musician aware of the tempo change.