Merged Accounts with only one account
If you have only one account and you activate the 'Merge accounts' preference you'll have a 'Merged accounts' row in your roster, quite strange i think. You'll also have a submenu for your only account in 'merged account' row context menu. The correct behavior should be to ignore this preference in a one account configuration.
I have tried to make a little gajim hack to adress this behavior. Strangely it seems to work so here it is.