Art dragged off the canvas reached the panels (Asset Export, Graphic
Styles, Swatches, Symbols) only from the Selection tool: drag_art_out
checked for that tool by id. With the Direct Selection or Group
Selection tool the move stayed on the canvas, so nothing dropped.
Those tools now hand over a move too when every selected object is
selected whole (a press on its fill). A drag of anchor points or
segments, which they also call Move, stays a reshape and isn't handed
to the panels.