Hint: check the upper/lower case in map entry.
FMB is case sensitive, while mission briefing mode is not.
Okay Andy, I got there finally, thank you very much, really appreciated.
I looked and looked but just could not see it, converted all kinds of text in the mission to upper case, even the ffb of the map, all
to no avail, just was blind to what in the end was staring me in the face.
Finally in desperation I made a mission just to check all was okay with the map and its objects, no problem, added a aircraft, saved it and then tried it out, all good.
I took the map title from the new mission and added it to mission 1 of the old campaign, loaded it up and launched it in the F.M.B., it worked, WTF.
So, what could I not see, a simple letter that in the title needed to go from lower case to upper as Andy said.
Note the highlighted letter guys and save yourself my frustration, from this:
MAP ffb_Thailand/
load.ini
To this:
MAP ffb_Thailand/
Load.ini
Even after all these years and as much time as I have spent with all aspects of it this sim still messes with my head.
Thank you very much to all of you for the help, really appreciated.
Take care and be safe.
Wishing you all the very best, Pete.