Creates a new <code>StyledTextDropTargetEffect</code> to handle the drag under effect on the specified <code>StyledText</code>.
@param styledText the <code>StyledText</code> over which the user positions the cursor to drop the data
See Implementation
Creates a new <code>StyledTextDropTargetEffect</code> to handle the drag under effect on the specified <code>StyledText</code>.
@param styledText the <code>StyledText</code> over which the user positions the cursor to drop the data