Hello Boris
I'm trying to use the same lib. I'm almost there :)
I don't have any problems with the innerRef, not that I know of, anyway. My problem is getting the "placeholder" React elements into the right places, with the right React->Reagent->React interop conversions.
To be clear, I'm just doing (.-innerRef provided) to get the ref.
My current state is; I've got elements lined up, being draggable, elements move out of the way for each other, and they are swapped upon drop (as I want them to). However, the first time I drag over another element, the surrounding container shrinks to fit all the elements minus the one I'm dragging, meaning that the ones that are moving out of the way are overlapping others. I'm pretty sure this is because I don't have the placeholder set up properly.
Let me know if you made any progress, or if you're still working on it. Maybe we can help each other out :)