Reporting Services Vertical Layout Not Sortable?

I recently switched a report from the usual table view (horizontal) to vertical because I had a ton of columns. The issue now is that when I click to sort nothing happens in the report itself. Does anyone know if it's possible to sort using a layout that is not horizontal? (using the default sort expression)

**Currently in the interactive sort dialog I have a checkbox to add an int sort action to this textbox. Next I have the second radio button selected "Choose data region or grouping" and I selected my dataset for this report

From stackoverflow

• when you say you switched to "vertical" layout, do you mean you are now using a Matrix, or are you using the newspaper style multi-column layout by adding columns to the body of the report?

  --thiago