You don’t need to edit any file.
And better avoid doing that if you are not sure of what you do.
The Bisq data directory locations are :
Mac OSX: /Users/username/Library/Application Support/Bisq
Windows 7,8,10: C:\Documents and Settings\username\AppData\Roaming\Bisq
Windows XP: C:\Documents and Settings\username\Application Data\Bisq
My suggestion is that, for your issue, if you are happy with some tuning (concerning eg account01) of your actual data directory, then, after closing, you duplicate (or just rename) the currently used data directory accordingly, and then use this directory when you want to use specifically this account01.
But I’m really surprised that selecting/deselecting accounts doesn’t work for you ?
Which Bisq version do you use ? with which OS ?