Need to find nessesary event.

Hello to all! When dragging block into canvas, and drop it: ... we have an event to detect, what block we drop in. ?: but when i drop block text, into form, (otherwords i nest one block into other) how can i detect : into what specific block nesting occurs?. What event is specified to detect such component. I've tried events canvas:dragenter and canvas:drop, but they dont bubbles , when drop component on canvas. Thank you to all community , who helping with! ps: somehow that events are never occurs