Izengrimm, now as I think we have understood, about what function you are talking (a function that I had never used in C3C), I have to say, you made a very interesting post in this thread, that could help to understand the mechanics behind C3C a little bit better.
I made a quick test of all C3C mods and scenarios that are on my pc and the astonishing fact is, that from the newer mods and scenarios (among them RARR, Worldwide, Giant Earth, EFZI Elite, TLC) only gwendoline´s MensWork has this function working on my pc. Older mods and scenarios like MEM and RAR have this function working, too. So for the readers of this thread, I try to explain the function with the mod MensWork:
When starting a mod or scenario and you click in the selecting-window of a civ on the field 'Game Limits', another window is popping up, showing you a lot of different settings for the game you want to start. This happens with all mods and scenarios. The 'special effect' in the mod 'MensWork' (and many older mods and scenarios) and the normal standard C3C game is, that the list of game settings here has a button in front of each option, that can be selected and allows the changing of the parameters of this setting.
Per example, if a player klicks on the option 'Turns' with the button in front of this option, another window is popping up where a player can change the setting of this option:
If the list has no buttons in front of these options, nothing can be changed here (only in the editor).
Now I made a change in the script file. The script file (in the texts folder) holds several functions of ending a normal game, a scenario game and a multiplayer game. The first settings for ending a normal game have a different structure than the other ending options.
I gave the CCM2 script file for the End_Game_Limits_Scenario the same settings as for the End Game Limits and now even when starting CCM2 as the Main Game, the pop-up-list shows the buttons in front of the options:
It seems the entry '#itemlist' in the script file is responsible for the appearing of the following entries as options connected with buttons. But my joy about that window only lasted for some seconds. When klicking on one of the options the complete window did close and no window to change the settings did pop up.
Also interesting in my eyes is the fact, that the script file seems to treat my CCM2 mainbiq as a scenario, as the changement in the End_Scenario settings influenced the first pop-up window of the new mainfile biq.
This is the stand of my current knowledge, unfortunately at present without a working solution. But I think these findings are interesting enough to post them here. It will be interesting to find, what most new mods and scenarios are missing, that older mods and scenarios and the new mod MensWork seem to have.
On the other side the current missing of that function (that always can be handled in the editor, too) has no known influence in the gameplay of CCM2 as the main biq and for all other mods and scenarios, that are missing that function, too.
Edit June 20,2019:
The problem is solved: In the Game Options of the Scenario Properties both Game Options must be set to Default. The changes in the script file are not necessairy. In CCM2 this will not happen as the Victory point scoring is needed for the supply shipments and at present, even now when I found an acceptable way to include the diplomatic victory to CCM 2, I think at present it is no good idea to give CCM2 the cultural victory option.