The MergeCells property has one setting that operates differently from the others. The flexMergeSpill setting causes text that is too long to fit in a cell to spill into empty adjacent cells. This setting does not require you to set the MergeRows() or MergeCols() properties.
For example, the picture below shows what a grid might look like when MergeCells is set to flexMergeSpill and the user types entries of varying lengths:
