As I tried to begin to document in the DCS6: To Do topic, one of the sections of Doors CS that I'm rewriting for DCS6 is the whole concept of associated programs, programs that can open data files. I decided that for Doors CS 6, the shell itself will handle most of the pointers and data transfer instead of relying upon the data file and main program to find the data and manipulate it. The first step was making Doors CS aware of data-only filetypes, which I suceeded in doing. For icons, I decided that data files, instead of having embedded icons, should get their icons from the main program. Therefore, some programs can now have an extended header that defines both an entry point other than $9D95 for when data is pending, filetypes that the program knows how to open, a dual icons: one for the program, and one for associated data files. In addition, I decided to pair main and data programs by a 3-byte data type identifier instead of the 8-byte ASCII name of the main program so that multiple competing programs can be made to open the same standardized filetypes. Check out the actual screenshot below that shows the working system in place. Note that the icons for both APMAIN and APTEST are inside the data structure of APMAIN; APTEST contains only a header and its 3-byte identifier with a short string for future testing use.