Change type of a placeholder element

[isetpro]

Hello! In my project it's need to change element's type when drag element changes its position. For example, first three elements should be like ElemA, and other should be like ElemB. These are different components. In static everything is OK, but when I'm dragging element a placeholder element appears, and it don't changes because it's copy of dragged element.

Q: How to change the placeholder element's type?