(This item pertains to the check boxes on the General tab of the Setup Options dialog box. You can open it through the F5 key or through the Edit | Preferences | Setup menu option.)
If you select the Lock Marked Sets check box, PC-DMIS will prevent users from accidentally deleting or otherwise modifying the current mark set configurations. PC-DMIS will only allow you to execute and activate marked sets. You must clear this check box to add or delete features from a marked set.