You have run into one of the classic problems with using merged cells, which many of us here consistently recommend against using. Your code checks to make sure only one cell has changed:
but when you delete a merged cell, you have changed 15 cells. So your code exits.
You can either reformat your sheet to avoid merged cells, or you can remove this test from your code. Although the first one is a better overall solution, the second one is probably easier.
This code will work no matter how many cells are changed, but it iterates through every changed cell individually.
Bookmarks