The Event Calendar tab of "Facts, Events & Exchanges" from the Database menu gives information about holidays and market closures. Use the arrows and scroll bar at right to scroll through the listing to the date you wish to investigate. The Event Calendar lets you know what markets, if any, were closed on the date in question. Here is an example:
You can replace the Event Calendar with a fresh download from CSI. See the "Download Replacement Files" topic for instructions.