Sorry for the delay!
What exactly do you mean by the "shadow"? Is that the semi-transparent div that indicates the target position during drag and drop? You can modify the appearance using CSS (create a theme using https://themes.daypilot.org/ and change the *_shadow style in the generated CSS).
If you want to disable the drag and drop you need to set individual *Handling properties to "Disabled", e.g.
dp.eventMoveHandling = "Disabled";
dp.eventResizeHandling = "Disabled";
dp.timeRangeSelectedHandling = "Disabled";