Boolean specifying if the draggable Panel should be drag only, not interacting with drop
targets on the page.
When set to true, draggable Panels will not check to see if they are over drop targets,
or fire the DragDrop events required to support drop target interaction (onDragEnter,
onDragOver, onDragOut, onDragDrop etc.).
If the Panel is not designed to be dropped on any target elements on the page, then this
flag can be set to true to improve performance.
When set to false, all drop target related events will be fired.
The property is set to false by default to maintain backwards compatibility but should be
set to true if drop target interaction is not required for the Panel, to improve performance.