If there are vertically merged cells, the Rows property is not valid; and
similarly, if horizontally merged then the Columns is invalid. You can test
the table's Uniform property if you need to check, or just trap the error.
This is one instance (the only one that I know of, in fact) where the
Selection object provides a function not available wsith Range objects. Even
when there are merged cells, you can still select columns and rows using the
mouse ...