give drop zone its own cursor-ability

gtk2_ardour/editor_canvas.cc

@@ -1325,6 +1325,7 @@ Editor::choose_canvas_cursor_on_entry (GdkEventCrossing* /*event*/, ItemType typ
 	case CdMarkerBarItem:
 	case VideoBarItem:
 	case TransportMarkerBarItem:
+	case DropZoneItem:
 		cursor = which_grabber_cursor();
 		break;
 

gtk2_ardour/editor_canvas_events.cc

@@ -1126,6 +1126,12 @@ Editor::canvas_drop_zone_event (GdkEvent* event)
 		return canvas_scroll_event (&scroll, true);
 		break;
 
+	case GDK_ENTER_NOTIFY:
+		return typed_event (_canvas_drop_zone, event, DropZoneItem);
+
+	case GDK_LEAVE_NOTIFY:
+		return typed_event (_canvas_drop_zone, event, DropZoneItem);
+
 	default:
 		break;
 	}

gtk2_ardour/editor_items.h

@@ -61,6 +61,7 @@ enum ItemType {
 	MinsecRulerItem,
 	BBTRulerItem,
 	SamplesRulerItem,
+	DropZoneItem,
 
 	/* don't remove this */