I have a little lack, because when my colleagues use QGIS, sometimes they make a mistake with merge function, but singlepart/multipart isn't solution.
The split tool cannot be use in this situation, because these polygons not neighbouring. I see all vertices in vertex editor dialog, but dont separate polygons.
Opposite if I use ArcGIS sketch properties, which shows separate the polygons.
ArcGIS use part(x) separate lines, which help to the identification of the polygons, hereby separates objects.
I want to similar solution in QGIS, that capable this task but didn't find suitable tool/plugin