Improvements to active deck selection

Currently, the selection of the active deck for “Match” is based on the position of the crossfader. In the case of using a controller, this is not suitable for everyone. It is much more logical in my opinion to use the opposite deck as an active deck. For example, if I select a track for deck 1, then the active deck is deck 2. If I open a playlist without selecting a deck, the interface switches to custom mode.