When adding or removing an account from lists, we currently can't see whether an account is now on the list or not, and the system is also not confirming when being added or removed.
While in a single account it would be very helpful it should only have available the option to change from current status, meaning to say if an account is not on the list, it should only have the option to add, if it is on list it should only have option to remove, or you can just make a popup confirming the last action done.
while in mail merge screen it would be very helpful to make any kind of symbol whether an account is on list or not, such like making bold or italic, or adding a new column with a checkmark for those on list.