When the Check In Region button in the DRC Menu is active, design rule checking is performed on objects the user clicks on or drags over. The method of selecting a region to check is the same as for the Check In Foreground command, however the Enter key is ignored. Violating objects are marked, the error region highlighted, and a pop-up explains the error. No file is produced. A maximum of 15 errors are accumulated for each region -- the check terminates at this error count. The Check In Region command button remains active until explicitly terminated, unlike the Check In Foreground command.