Fixed activity results. Fixed background file setting.
Sound does not disappear when placed to its own slot.
Define sound slot using sound middle point instead of event point. Using event point is bogus when using fine tuning.
Removed double checkpont on auto-arrange sound placing.
Sound is well-formed when created in auto-arrange mode.
Sound can be pasted multiple times repeatedly.
Background image nullcheck when using is enabled.
Add option to default backgound image.
Release v0.23