If your items do not have inplace editing, did you try
Planner.DefaultItem.ReadOnly = true and Planner.DirectMove = true? This way, you should be able to touch anywhere on the item and directly drag the item to a new position.
It's the way it's setup in my case. Works fine for the mouse. But on new touch screens, I have the feeling that the drag is not handled properly. When taping and draging on an item, it's scrolling the planner instead of the item that was tapped (even if item has been previously selected). I'm even not sure the component is getting the down event properly from Windows. In rare cases, with the perfect timing, the item gets dragged.
Maybe it's a matter of touch configuration on this machine?
I finally found a solution around this problem. I've added a message handler that catch WM_POINTERDOWN events. If the touch is inside a calendar meeting, I stop propagation and send a WM_MOUSEDOWN event to the planner grid. I then replace pointer update events with mouse move events and pointer up with mouse up. With that work around, users are again able to drag calendar items on touch devices running Win8 or later.
Thanks for informing. Do you handle this at form level or at Planner level?
As we already had an event procedure at application level, we used that one for the tests. But it's probably possible to manage the event at planner level.