The portlet columns will now display only those portlets explicitly assigned in this context. Use the buttons on each portlet to move them up or down, delete or edit them. To add a new portlet, use the drop-down list at the top of the column.
If you wish to block or unblock certain categories of portlets, you can do so using the drop-down boxes.
There are legacy portlets defined here. Click the button to convert them to new-style portlets.