Move DnD marker node to task_grid contrainer area


it should not created on document node, and it cause a problem: the task row could be drag outside the gantt container area:


Hello Kevin,
Thank you for informing about the bug. I was able to reproduce it in regular snippets and looks like, it happens only with the marker mode.
I added the bug in the tracker, and the dev team will fix it in the future. I cannot give you any ETA, but I will notify you when it is fixed.