I am seeing the same issue, but I've never tried to filter Items before so I don't know how long that has been going on. Typically I use the compendium on a per-book or on a "search for a specific thing" basis. The only category I typically use is Spells and for that "filter results" appears to work. It may just be that it hasn't ever come up as a bug before as I haven't seen it reported before. Since the forums are primarily for users helping users I would suggest filing a bug report on it with the Devs via the Help Center . In the meantime, I would use the compendium search function for the item you are looking for, or the book you are looking for. For example, for items I typically just head to the Player Handbook's equipment chapter in the compendium.