Actually, I think you want to right click on the heading of the preview pane and select OPEN PREVIEW. This will open up the AR Invoice History Detail data for all invoices, not just the one you have selected in the header pane.
The nice thing about this is that you can modify this view and save it as a new setting.
The trick to see the saved setting of the detail data is to first go to the standard view of the header, then right click on the detail pane and select OPEN PREVIEW like you did originally. Then you sill see your saved setting in the drop down list.
I have found this to be useful for clients who do sales reporting by customer and item, since I can pull in all the header fields too.