I visited a friend recently, who lives in Münster, Westfalen. I had his address but looking for it with navigator was really tedious. In the first step there is a choice between Münster (...) and Münster (Hessen), in the choice Münster (...) Navigator listed 15 Münster in Germany just as Münster, Münster#2 to Münster#15, starting with Münster, then Münster#10 to Münster#15, then Münster#2 to Münster#9. Actually I gave up, looked at Google Maps for the address and searched and marked it directly on the map in navigator.
Postcode search in the field Wähle Ort/Region/Postleitzahl does not work at all.
I had another example around the same days, which I do not remember now.
Navigator should specifiy in more detail the city as it does with Münster (Hessen) already.