How can a drop-down validation list be created in MS Excel that spans two columns?

edit

To create a drop-down validation list that spans two columns in MS Excel, follow these steps:

1. Select the cells in which you want to create the drop-down list.

2. Click on the "Data" tab in the Ribbon.

3. Click on "Data Validation" in the "Data Tools" group.

4. In the "Settings" tab, select "List" from the "Allow" drop-down menu.

5. In the "Source" field, enter the values you want to include in the dropdown list, separated by a comma. For example, "Red, Blue, Yellow".

6. Click on the "OK" button.

7. Now, the cells will have a drop-down list with the values you entered.

8. To span the drop-down list over two columns, select the cells in the second column and go back to the Data Validation window.

9. In the "Source" field, add the same comma-separated values as in the first column, but with an ampersand symbol (&) and a space before the first value. For example, "Red, Blue, Yellow" becomes " & Red, Blue, Yellow".

10. Click on "OK" and the drop-down list will span both columns in the selected cells.

Note: If there are more values in the second column than in the first, the drop-down list will display the additional values only in the second column.