Returns: is cell-merging of the selected cells possible?
function CanMergeSelectedCells(AllowMergeRC: Boolean): Boolean;
The same as CanMergeCells, but potential area for cell-merging is the selection in the table.
If AllowMergeRC=True, this function returns False, if one or more rows or columns will contain only nils after merging. It's not recommended to have such rows/columns, so you can either forbid such operation or (better) delete them with DeleteEmptyRows and DeleteEmptyCols.
This method can be used to determine if the selection in the table has a rectangular shape.
This method must be called when the document is formatted.