When in the LIBRARY menu and in the INSTR. tab below that, when scrolling through the entire list, Spark will open up the last sound you land on. If you leave it a few seconds the blue task bar shows it loading, yet if you move onto another drum pad to search for a new sound, the previous sound isn't saved. You have to let the sound open, then click the scroll wheel in order for it to save the selected drum before moving on to edit a new drum sound. You have no reporting when you click the wheel to say that the sound has opened, this happens when you scroll though the list but doesn't save the selection.