Just as the title says,
I had this problem for a while and couldn’t figure out, but it seems that GAO does not allow processed audio material (eg. Normalize, Gain) for drag drop.
Any work around? I want to do this because I have a guitar part too small in volume so I normalized a couple of sliced parts, but it doesn’t allow me to drag drop those to GAO after process. All untouched imported audio materials are drag drop capable. BTW I drag drop directly from the project window.