You may use rve.ItemCount to see if TRichViewEdit is really empty. This means nothing at all. If rve is cleard but not formated, the value returned is 0. If it is formatted, the value returned is 1.
function RVEmpty(MyRichView: TCustomRichView): Boolean;
begin
Result := (MyRichView.ItemCount = 0) or ((MyRichView.ItemCount = 1) and
(MyRichView.GetItemStyle(0) >= 0) and
(MyRichView.GetItemText(0) = ''));
end;