Can't go into advanced mode in SSRS 2008 R2

Question

I cannot find advanced mode in SSRS 2008 R2. I need to freeze the top row in a tablix so it stays there when scrolling on a report. Apparently I can do this in "advanced mode", but when I click the arrow to the right of the groups in the grouping pane, I do not have the advanced mode option.

Answer 1

Check this screenshot:

I think you are clicking on the row groups arrow. Let me know if this helps.