"Error reading _1. Views: Stream read error" during a Describe of a SYS object in the Editor. (4319502)

When logging in with a system user account and trying to describe any object from the SYS schema from the Editor window, the following error message is displayed:

"Error reading _1.Views: Stream read error".

Steps to reproduce:

1) Login as system or sysdba
2) Open a new Editor window
3) Type in the name of an object that belongs to the sys schema (i.e.: dba_users)
4) Press F4

Expected results:
The 'Describe Objects' screen opens

Actual results:
"Error reading _1.Views: Stream read error" is displayed.