You can drag one or more cells with data validation to autofill cells on the left, right, bottom, or top.
You can cut, copy and paste cells with data validation.
When you merge cells, the data validation condition is saved only from the upper-left cell of the range.
When you split cells:
•The data validation condition is retained in the upper-left cell of the range if it was defined for that cell before the cells were merged.
•The data validation condition is retained in each cell of the range if it has been defined for the merged cell. If the merged cell contained a drop-down list and a value was selected in it, it will only be retained in the upper-left cell of the range.
If a column or row that contains cells with data validation is selected on the sheet, the cells with data validation are copied to the new columns/rows when new columns or rows are pasted.