Vertical Lists, Bullets

Q. Two colleagues and I are disagreeing at work about the formatting of the text above vertical lists. The introductory element is often a few words, and it is usually not a complete grammatical sentence, yet we end the introductory element with a colon. One woman declared that this was wrong and that we should fix thousands of screens in hundreds of lessons by either rewriting the introductory element as a complete sentence or removing the colon. What do you think?

A. In new text, I would edit as your colleague suggests, but since it sounds like a costly and time-consuming process for you to change the ones you already have in place, you might compromise by replacing the offending intros only as you add new lessons or revise old ones.