Actor Constructor called twice

It seems that the constructor for an Actor is called twice.
When you start dragging a class from the class browser (or a blueprint deriving from it from the content browser) into the world, one instance gets created that is shown while you keep dragging. Then when you release the mouse and the Actor is placed in the world, another instance of the Actor is created at that location, and the old one gets deleted by the garbage collector sometime later.

Now my question is, how can I detect if I’m in such a temporary instance in C++ or blueprints? Is there anything unique about these temporaries that I could use to identify them?

There is a function available for this - UObject::IsTemplate(), but i’m not sure what flag you have to pass to the function to check if it’s preview actor; it’s RF_Transient probably.

RF_Transient works perfectly. Thank you!