select window is pop up on top left of display

On wayland session, ibus (or wayland or gtk) display selection window on top left of the display.

No problem on xorg session.

How to reproduce:
1. Install artful
2. Install ibus-mozc (or install artful as Japanese locale)
3. Login to wayland session
4. Startup gedit or gnome-terminal
5. Press Hankaku/Zenkaku (or enable Japanese input method)
6. Type any words and press space

Expected result:
The select window pop up on bottom of the cursor.

Actual result:
The select window pop up on top left of the display.

Fireforx hasn't any problem.

ProblemType: Bug
DistroRelease: Ubuntu 17.10
Package: ibus 1.5.14-2ubuntu1
ProcVersionSignature: Ubuntu 4.13.0-12.13-generic 4.13.3
Uname: Linux 4.13.0-12-generic x86_64
ApportVersion: 2.20.7-0ubuntu2
Architecture: amd64
CurrentDesktop: ubuntu:GNOME
Date: Tue Oct 3 21:46:09 2017
InstallationDate: Installed on 2017-09-18 (14 days ago)
InstallationMedia: Ubuntu 17.10 "Artful Aardvark" - Alpha amd64 (20170917)
ProcEnviron:
 TERM=screen-256color
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=ja_JP.UTF-8
 SHELL=/bin/bash
SourcePackage: ibus
UpgradeStatus: No upgrade log present (probably fresh install)