Refactoring of Drag and Drop complete. Draggable properties isUsable, isOriginal included, but functionality connected with them is not complete. Found and fixed bug with z-index ordering.

New feature: Clicking on number for multiple icons on target will cycle all icons on target. Fixed bug with z-order ordering.

New feature: added ability to define custom label background color. Upated demo to use this feature. Needs to be turned on Python side.

New feature: when the draggable is out of the slider container, if it has a label, the label will get a background. This way it is much easier to discern the label against the base image.