I want to edit PostGIS layers within QGIS and before that, I changed a layer using ST_Difference. Now, I can select QGIS' Edit Feature after importing it from PostGIS but only for some layers it is possible (which I haven't changed) to change their vertices with the Vertex Tool.
I checked SRID, Geometry Type and so on but couldn't find a difference. Has anyone ever faced the same problem?