How to use the Selection drop-down of Generate DDL Script window?
1. Uncheck/check desired property names from list and select the Save icon. Give the selection a name.
2. Reselect "Default Selection" option from drop-down and select the Load icon (red down arrow icon). This will change list setting back to default.
3. Select your defined selection from Step 2 from drop down and again select Load icon. The list selection will revert back.