Hello again,
I recently upgraded to the latest nightly build, and when drag-and-dropping from a grid to the scheduler, the event seems like it's dropping onto the row in the scheduler that's level with the row on the grid, rather than where I dropped it.
I'm able to replicate this on your drag-from-grid example using your 4.1.0-beta-2 release, along with the nightly build from 2/24 and 2/25. It works on the 4.0.8 build. To replicate, on the drag-from-grid example, try dragging the first object on the grid to an available spot in the scheduler somewhere below it.
This issue seems to be particular to with Firefox -- Chrome / Edge is ok.