diff --git a/tiling.js b/tiling.js
index 2c99372..10e39a9 100644
--- a/tiling.js
+++ b/tiling.js
@@ -1453,11 +1453,11 @@ function centerWindowHorizontally(metaWindow) {
     const frame = metaWindow.get_frame_rect();
     const space = spaces.spaceOfWindow(metaWindow);
     const monitor = space.monitor;
-    const targetX = (monitor.width/2 - frame.width/2)
+    const targetX = Math.round(monitor.width/2 - frame.width/2);
     const dx = (targetX + monitor.x) - frame.x;
     utils.warpPointerRelative(dx, 0);
-    move_to(space, metaWindow, { x: targetX, y: frame.y });
-    space.emit('move-done');
+    move_to(space, metaWindow, { x: targetX, y: frame.y,
+                                 onComplete: () => space.emit('move-done')});
     Tweener.removeTweens(space.selection);
     space.selection.width = frame.width + prefs.window_gap;
     space.selection.x = targetX + monitor.x - Math.round(prefs.window_gap/2);