tested version with most of the final functionality. Still a few known issues, like dragging to a row that extends to multiple lines

card.cs

@@ -124,7 +124,6 @@ public partial class card : Panel
 	}
     public override Variant _GetDragData(Vector2 atPosition)
     {
-		GD.Print($"starting to drag {CardId}");
         var prev = card_preview.MakePreview(this);
 		var prev_root = new Control();
 		prev_root.AddChild(prev);