Currently double-clicking on a track somewhere in the library adds it to the first non-playing deck. However, when four-decks-mode is activated and both of the two original decks have tracks in them, even if one isn't playing, double-clicking a third track in library merely switches out the second track from the non-playing second deck. Decks two and three remain empty unless tracks are manually dragged to them; double-clicking will never fill them.
It would be intuitive if decks got filled to capacity, i.e. as long as there is an empty deck, double-clicking a track will get that track sent to one of them.
Currently double-clicking on a track somewhere in the library adds it to the first non-playing deck. However, when four-decks-mode is activated and both of the two original decks have tracks in them, even if one isn't playing, double-clicking a third track in library merely switches out the second track from the non-playing second deck. Decks two and three remain empty unless tracks are manually dragged to them; double-clicking will never fill them.
It would be intuitive if decks got filled to capacity, i.e. as long as there is an empty deck, double-clicking a track will get that track sent to one of them.