In a message Russ mentioned the Ardennes theatre, so I found it. This theatre covers the site of the Battle of the Bulge, from the 16th of December 1944 to the 25th of January 1945.
During this time the frontline was really changing, and the frontline system in EAW is hardly appropriate for a situation like this.
The "frntline.dat" file has 20 frontlines 0-19. In single missions 1940 uses 0, 1943 uses 0, 1944 uses 8 and 1945 uses 12.
A while ago I programmed UAW160 to read a "Frontline.mpf" file to vary this. I have just used one which reads
These are the respective frontlines for 1940, 43, 44 and 45, (replacing the 0, 0, 8 and 12)
I selected each one using the frontline editor to which I added additional code in order to do this, and save the file
The next problem is that if I fly a P47D then the earliest year is 1944 so I either get 13 or 17.
However, there is a UAW160 fix for that too
If the root folder or the theatre folder contains a file named "NoYear" then the year values for the aircraft are ignored.
When it is present I can fly a P47D in 1940 with frontline #9, or in 1943 with #11, or 1944 with #13 or 1945 with #17.
I can also make the four years display as "Phase 1", "Phase 2", "Phase 3", or "Phase 4".
This is not perfect, but now gives us the possibility of having four different front lines covering a short time period, such as the Battle of the Bulge