You can change your order of assets and their groups by
Settings > Configuration > Accounts Management > ⋮ button > Modify orders, or
Accounts tab > ⋮ button > Modify orders
Tap the Cash line and check-mark next to "Cash" on it. Then you can change orders by tapping the arrow marks on the top.
For example, like below, in case a group consists of only one category, if you move that category out of that group, Money Manager automatically hides the group from the list.
Should wish to make the hidden group appear again, just tap the account that you have just moved and re-select the group manually.
As you can see below, “Cash” group has been re-input manually.
“Cash” Group has re-appeared on your list of Account Groups.