class DetachTransitions;
class MuteSelection;
class TrimSelection;
+class MixerItems;
+class MixerViewer;
class TileMixers;
class AddAudioTrack;
class DeleteAudioTrack;
class TileWindows;
class SplitX;
class SplitY;
-class MixerViewer;
class LoadLayoutItem;
class LoadLayout;
class LoadLayoutDialog;