There seems to be a bug in UA Shell in relation to CKIT hacking and the creation of diff.tlb files. CKIT editing through UA Shell itself works fine: the version of ckit.exe in the UA Shell folder is changed as editors are used. Then when the designer is prompted "Save CKIT changes?" UA Shell is supposed to create an updated diff.tlb from the working version of ckit.exe and place it in the folder of the current applied design. But the diff.tbl which UA Shell creates invariably is a 1 byte file --- meaning that the CKIT editing just done, and any previous CKIT editing, is lost.
This has previously been noted elsewhere in these forums. I always run UA Shell through DOS Box and so I am not sure if the bug occurs only when UA Shell is run through DOS Box.
I have been getting around this by using Nol Drek's marvellous Java program to create diff.tlbs. This requires ALT-TABbing out of UA Shell before electing whether to save CKIT changes, creating a new diff.tlb from the working version of ckit.exe, making a backup of the new diff.tlb so created, then (after either saving or undoing the CKIT changes), replacing the diff.tlb created by UA Shell with the backup version. If done correctly, this method invariably works. But it is pretty laborious. UA Shell should be doing the work of Nol Drek's java programme itself.
So ... my question is: is it possible for someone with some programming experience, and a good understanding of US Shell, to update UA Shell to a new version which correctly creates a new diff.tlb from the working version of ckit.exe? Maybe all that is required is that answering "yes" to the "save CKIT Changes" prompt led to Nol Drek's java program being run, instead of whatever it is that UA Shell currently attempts to do? (I don't know if such a program can be run by a program that is running through DOSBox.)