On the New Bug form the "Component Description" says "Select a component to read its description." but selecting a component doesn't change it, so descriptions are never shown. It used to work until fairly recently. This is the case for all Products, as far as I can tell, but definitely for at least Fedora, RHEL7 and the Bugzilla product, so probably all others as well.
*** This bug has been marked as a duplicate of bug 1293554 ***