When building a custom Package in X3 Builder within VS Studio, it scans the list of X3 Activity Codes associated with the Package. It checks to see if any Activity Codes are also associated with other Packages, and will alert you if there are any occurrences.
If you see this message, review the list of Activity Codes in the Packages - the common one(s) will probably be at the field-level. In this case, there was an Activity Code on a custom table that is also on a standard table within the Sales Package.
Change the custom Package to remove Activity Codes associated with other Packages.