Blank Option in Highlight Row when Answer in this Column Field

Why there is a blank option in the Highlight Row when Answer in this Column field in the Edit Dynamic Table window

If you don't enter a name for a column in the Column Label field, there will be no option displayed in the Highlight Row when Answer in this Column drop-down list in the Edit Dynamic Table window. For example, Let's say you have a dynamic table with 3 columns, and you only name the second column (in the following example, the second column is named "Test").

When you click the (edit) icon for the dynamic table to open the Edit Dynamic Table window, you'll notice that the Highlight Row when Answer in this Column drop-down list displays a blank for each column without a label (in the following example, there is a blank line for the first and third column since they were not named).