Dynamic Frozen Column example hangs

In FireFox 37.0.1

I open http://localhost:8080/isomorphic/system/reference/SmartClient_Explorer.html#dynamicFreezeFS

I right click on the "Item" column title and click on "Freeze Item".

I right click on the "Category" column title and click on "Freeze Category".

I right click on the "Item" column title, click on "Columns", and then click on "Description" (to deselect it).

The browser hangs, and then FireFox opens a dialog telling me the script has become unresponsive.

Google Chrome 41.0.2272.118 (64-bit) also hangs following these steps.

SmartClient version: v10.0p_2015-04-05/EVAL Development Only

Andrew