Fences no longer automatically reorganizes icons

Previously, if I resized a fence, the ions within would reorganize to remain visible in the viewspace. For example, if I made the fence tall and skinny, the icons would arrange themselves into a single vertical column to remain visible.

Now, the icons don't move when I resize a fence. They remain in their original locations and often disappear from view on fence resizing. How can I restore the original behavior?