With classic/ 2.x skins like you screenshot then if you make the drop on the bottom area of the main playlist window outside of where the list contents are shown then it should add those new items a t the bottom of the playlist even if that's not where the contents are showing. The same also applies to the top area of the window iirc. For winamp3 / modern style skins that handling isn't supported due to how they're implemented.
I'm not going to add empty space especially as unlike winamp I have it coded my main playlist implementation to be able to show partial playlist lines at the bottom instead of clipping things to full lines & being more confusing imho when trying to work out if there is more still to be shown or not.
