I think I figured out why it doesn't refresh on drag/drop but I'm still having refresh issues.
For example on a context menu click it changes some properties of the task so the control used to display the task is not the same.
Without moving my mouse over it doesn't refresh it. And that's the same for other actions. I'm not sure how the refresh is handled and this is maybe why we are having issue because we miss something.
And also I have a different behavior concerning the resize action and the drag drop action. Both use the same container for a task, but if I start first by dragging then I have the drag/resize control appearing, but if I start by reisizing but then it doesn't work at all. I can't figure out what's the difference in the control handling to cause such issue.
I attach two gif showcasing the problem, note that each capture run under the same code, and is done after a fresh boot of the application.