Let me try to rephrase... When the re-size procedure is triggered it appears to be turning on the locked indicator in one of the cells that make up the total merged cell (maybe that's why it's displaying a square instead of the check on the lock indicator.

As I understand it, in order for user to be limited to enter data into only certain cells you set the locked indicator to on for those cells and set it to off of the cells you want editable. When protecting the sheet I am only allowing modification to unlocked cells.

What appears to be happening when the procedure triggers is that it re-sizes the merged cells and then turns on the lock indicator in one of the cells that make up the merged cell, thus locking the entire merged cell to further modification once the procedure re-enabled the sheet protection.

Does that make sense?