Objects with no layers

Some objects dont have any layers assigned to them.
How to make an object not fall in any layer??

 

Objects always have a layer. Choose 'Default' to assign to 'No layer'

 

Some objects in my game are having a blank layer or no layer

 

Perhaps those are cases where they had a layer assigned, but you then deleted that layer from the layers in the project?

This might also happen if you import some objects from another project, and they were using layers in that project that don't exist in this one.

EDIT: In any case, @BoredMormon is correct, this is not a normal situation and not something you should attempt to do. Instead, assign objects to Default if there is not some other layer more suitable for them.