There have been a number of cases of user confusion when changing the sources for a character. In order to alleviate this the user should be told that they are switching sources when loading a character and be given the option of not changing the sources.
User loads a set of sources
User loads a character which the same set of sources
System loads the character
User loads a character with the same game mode but a different set of sources
System advises user that the sources are different and asks them if they want to switch to the character's sources.
If yes, as currently all other characters are closed, the new source is loaded ad the character is loaded.
If no, the existing characters and sources are retained and the character is loaded using the existing sources - errors are dealt with in the normal manner.
If cancel, no load happens and existing characters and sources are retained.
User loads a character with a different game mode
System unloads existing characters and sources, then loads character';s sources and the character. (i.e. as currently occurs)