I have two layers, a point layer and a polygon layer ('Sektorplan'). The polygon layer attribute table has a "Sektor" column ('1','2', ...).

The Goal

I want to add a new column ("Sector") to the attribute table of the point layer to indicate in which sector the point is located.

Tried so far

I used overlay_within('Sektorplan', Sektor) in the field calculator of the point layer.

The Problem

The resulting column only shows NULL. Using a Virtual Field or not does not make any difference. The preview of the field calculator shows up correct (['1']).

Pictures say more than a thousand words

Anyone knows what causes this? My search-fu failed me.