I have several WordPress 2.3.1 installations. On one of them, if I attempt to use the Category filter in the Manage Posts administration panel, it always lists all posts -- not just the ones for the category I chose. At the top of the window, it says:
Posts in ""
As if I searched for a blank category field.
Other than installed plugins (which are similar but not exactly the same), the only difference between this install and one that works okay is the version of MySQL: 4 (doesn't work) vs. 5 (works).
Is this my problem or could it be something else?