This is not a question, just a post to follow up on:
https://www.msofficeforums.com/word-...able-cell.html
A dozen years or so ago, out of general frustration with Microsoft's half baked Content Control events, I developed a VBA process for the purpose of detecting user changes made while typing in a content control.  It is not pretty or easy but solved a problem I had at the time.
 Some time later, I discovered that I could use a similar process to create Word table cell events i.e., OnEnter, OnExit and OnChange:
Word Table Change Events
In that article I had demonstrated limiting cell text to a set character count e.g., 10 characters or 25 characters.
In the attached document, I have changed Paul's procedure to a function and incorporated it to demonstrate a method of limiting text to a set line count.
Constructive comments or suggestions for improvement always welcome.