Fixed coordinate retrieval in update function

grab.js

@@ -85,11 +85,11 @@ export class MoveGrab {
         center && clone.set_pivot_point(0, 0);
 
         this.signals.connect(this.actor, "button-release-event", this.end.bind(this));
-        this.signals.connect(this.actor, "touch-event", (evt) => {
+        this.signals.connect(this.actor, "touch-event", (act, evt) => {
             if (evt.type() == Clutter.EventType.TOUCH_END)
                 this.end();
-            else if (evt.type() == Clutter.EventType.TOUCH_UPDATE)
-                this.motion(this.actor, evt);
+            else
+                this.motion(act, evt);
         });
         this.signals.connect(this.actor, "motion-event", this.motion.bind(this));
         this.signals.connect(global.display, "window-entered-monitor",
@@ -307,6 +307,8 @@ export class MoveGrab {
         let metaWindow = this.window;
         // let [gx, gy] = event.get_coords();
         let [gx, gy, $] = global.get_pointer();
+        if (event.type() == Clutter.EventType.TOUCH_UPDATE)
+            [gx, gy] = event.get_coords();
         let [dx, dy] = this.pointerOffset;
         let clone = metaWindow.clone;