"Add to area" makes arrows freeze?

I have a diagram with rectangles and arrows. I want to add them to a new area. When I select all and add to area, the arrows are hidden behind some of the rectangles. I can't select the arrows or manipulate them in any way, even if I move the rectangle in front of them. I also can't reorder the rectangles (send to back) to get the arrows back into position--when I try, nothing happens. What is going on? Is there a way around this? Is it a bug? Any help is appreciated.

Example: before

After adding all to an area. The arrows are hiding and they won't come out!

thank you!!