When loading a modlist, the behavior exhibited is that the selected .html will replace whatever is currently loaded. A helpful option would be for the selected list to add without replacing.

A use case for this would be: I have a modlist A that was provided to me by a friend with which to play, and I have clientside mods that I would like to load in addition to that. Said clientside mods are not in modlist A because while I want them for my own experience, my friend does not. Currently, the way this must go is that I load modlist A, and then must go down my list of mods and manually enable all of my clientside mods-- usually the same ones every time, and the list can be anywhere from 20 to 40 mods. This can be annoying and time-consuming when modlists frequently get updated or replaced.

The workaround which I have prepared is to have all my clientside mods condensed into a single local mod, and then enable that in lieu of all the individual Workshop mods. However, I don't know what problems this could cause in the future as I haven't had a chance to try it.

A preferable alternative would be if I could simply have my clientside mods in a second modlist B, and then when a new modlist A is received, I can just load modlist A and then load modlist B. Modlist B simply gets added to modlist A in the currently loaded mods. If any mods exist in both A and B, they can be ignored and thus only loaded in modlist A.