diff --git a/js/ui/boxpointer.js b/js/ui/boxpointer.js
index 68cea44eb..916005a9f 100644
--- a/js/ui/boxpointer.js
+++ b/js/ui/boxpointer.js
@@ -264,6 +264,92 @@ BoxPointer.prototype = {
         cr.stroke();
     },
 
+    setPosition: function(sourceActor, gap, alignment) {
+        let primary = global.get_primary_monitor();
+
+        // We need to show it now to force an allocation,
+        // so that we can query the correct size.
+        this.actor.show();
+
+        // Position correctly relative to the sourceActor
+        let [sourceX, sourceY] = sourceActor.get_transformed_position();
+        let [sourceWidth, sourceHeight] = sourceActor.get_transformed_size();
+
+        let [minWidth, minHeight, natWidth, natHeight] = this.actor.get_preferred_size();
+
+        let resX, resY;
+
+        switch (this._arrowSide) {
+        case St.Side.TOP:
+            resY = sourceY + sourceHeight + gap;
+            break;
+        case St.Side.BOTTOM:
+            resY = sourceY - natHeight - gap;
+            break;
+        case St.Side.LEFT:
+            resX = sourceX + sourceWidth + gap;
+            break;
+        case St.Side.RIGHT:
+            resX = sourceX - natWidth - gap;
+            break;
+        }
+
+        // Now align and position the pointing axis, making sure
+        // it fits on screen
+        switch (this._arrowSide) {
+        case St.Side.TOP:
+        case St.Side.BOTTOM:
+            switch (alignment) {
+            case St.Align.START:
+                resX = sourceX;
+                break;
+            case St.Align.MIDDLE:
+                resX = sourceX - Math.floor((natWidth - sourceWidth) / 2);
+                break;
+            case St.Align.END:
+                resX = sourceX - (natWidth - sourceWidth);
+                break;
+            }
+
+            resX = Math.min(resX, primary.x + primary.width - natWidth);
+            resX = Math.max(resX, primary.x);
+
+            this.setArrowOrigin((sourceX - resX) + Math.floor(sourceWidth / 2));
+            break;
+
+        case St.Side.LEFT:
+        case St.Side.RIGHT:
+            switch (alignment) {
+            case St.Align.START:
+                resY = sourceY;
+                break;
+            case St.Align.MIDDLE:
+                resY = sourceY - Math.floor((natHeight - sourceHeight) / 2);
+                break;
+            case St.Align.END:
+                resY = sourceY - (natHeight - sourceHeight);
+                break;
+            }
+
+            resY = Math.min(resY, primary.y + primary.height - natHeight);
+            resY = Math.max(resY, primary.y);
+
+            this.setArrowOrigin((sourceY - resY) + Math.floor(sourceHeight / 2));
+            break;
+        }
+
+        let parent = this.actor.get_parent();
+        let success, x, y;
+        while (!success) {
+            [success, x, y] = parent.transform_stage_point(resX, resY);
+            parent = parent.get_parent();
+        }
+
+        // Actually set the position
+        this.actor.x = Math.floor(x);
+        this.actor.y = Math.floor(y);
+    },
+
     // @origin: Coordinate specifying middle of the arrow, along
     // the Y axis for St.Side.LEFT, St.Side.RIGHT from the top and X axis from
     // the left for St.Side.TOP and St.Side.BOTTOM.
diff --git a/js/ui/popupMenu.js b/js/ui/popupMenu.js
index 60f9011b1..889f29622 100644
--- a/js/ui/popupMenu.js
+++ b/js/ui/popupMenu.js
@@ -550,7 +550,6 @@ PopupMenu.prototype = {
 
         let [minWidth, minHeight, natWidth, natHeight] = this.actor.get_preferred_size();
 
-        let menuX, menuY;
         let menuWidth = natWidth, menuHeight = natHeight;
 
         // Position the non-pointing axis
@@ -573,68 +572,8 @@ PopupMenu.prototype = {
                     this._boxPointer._arrowSide = this._arrowSide = St.Side.LEFT;
             }
         }
-        switch (this._arrowSide) {
-        case St.Side.TOP:
-            menuY = sourceY + sourceHeight + this._gap;
-            break;
-        case St.Side.BOTTOM:
-            menuY = sourceY - menuHeight - this._gap;
-            break;
-        case St.Side.LEFT:
-            menuX = sourceX + sourceWidth + this._gap;
-            break;
-        case St.Side.RIGHT:
-            menuX = sourceX - menuWidth - this._gap;
-            break;
-        }
 
-        // Now align and position the pointing axis, making sure
-        // it fits on screen
-        switch (this._arrowSide) {
-        case St.Side.TOP:
-        case St.Side.BOTTOM:
-            switch (this._alignment) {
-            case St.Align.START:
-                menuX = sourceX;
-                break;
-            case St.Align.MIDDLE:
-                menuX = sourceX - Math.floor((menuWidth - sourceWidth) / 2);
-                break;
-            case St.Align.END:
-                menuX = sourceX - (menuWidth - sourceWidth);
-                break;
-            }
-
-            menuX = Math.min(menuX, primary.x + primary.width - menuWidth);
-            menuX = Math.max(menuX, primary.x);
-
-            this._boxPointer.setArrowOrigin((sourceX - menuX) + Math.floor(sourceWidth / 2));
-            break;
-
-        case St.Side.LEFT:
-        case St.Side.RIGHT:
-            switch (this._alignment) {
-            case St.Align.START:
-                menuY = sourceY;
-                break;
-            case St.Align.MIDDLE:
-                menuY = sourceY - Math.floor((menuHeight - sourceHeight) / 2);
-                break;
-            case St.Align.END:
-                menuY = sourceY - (menuHeight - sourceHeight);
-                break;
-            }
-
-            menuY = Math.min(menuY, primary.y + primary.height - menuHeight);
-            menuY = Math.max(menuY, primary.y);
-
-            this._boxPointer.setArrowOrigin((sourceY - menuY) + Math.floor(sourceHeight / 2));
-            break;
-        }
-
-        // Actually set the position
-        this.actor.x = Math.floor(menuX);
-        this.actor.y = Math.floor(menuY);
+        this._boxPointer.setPosition(this.sourceActor, this._gap, this._alignment);
 
         // Now show it
         this.actor.reactive = true;