Use of value list greatly slowing portals and layouts

My Setup:

Orders layout based on Orders table.

Portal on orders layout based on OrderLines table.

OrderLines table stores fields: OrderLineID, ItemID, Price.

Item table stores fields: ItemID, ItemName.

If each orderline in the portal displays only the OrderLineID and the ItemID (both fields in the orderlines table). This works well and is fast. Since I want to display the ItemName instead of the ItemID, I am using a pop-up menu style control with a value list based on the Item table. The value list is set to use values from the Item table with ItemID as the first field and also display values from a second field, but only show values from the second field. This way, the portal shows the OrderLineID and the ItemName, which is what I want. However, this slows portal scrolling greatly. It also slows the Orders layout when browsing through order records. There is about a 1 sec delay in scrolling in the portal and about a 2 second delay when browsing through order records. All of the fields involved are indexed. This seems like too much of a slowdown to be acceptable.

I am using FM11 Pro Advanced. So...

1. Is this kind of slowdown typical? It seems to me that this would be a very common use of value lists.

2. Is the slowdown due to indexing of fields? Should I NOT index certain fields?

3. Are there faster ways to do the same thing?

Thanks!

Paul