I have multiple collections in Scene Collection. For some reasons, Blender always put new mesh into a specific collection instead of just in general scene collection. How does Blender determine where to place new object in scene collection?
It is put in the last select collection, which was selected in the outliner.
1 Like
@rigoletto is right. It is placed in the collection that was selected.
See this grey rounded square on the collection icon? 
That was the last selected collection, and objects will be placed in it.
If you want objects to go into no collection, click the top scene collection to ensure that: 
See the grey square there too.
1 Like