IBUS-WARNING when some applications are run in a VNC session without a window manager

Some applications, such as gedit, generate messages like the following when run in a VNC session without a window manager:

        (gedit:9710): IBUS-WARNING **: Events queue growing too big, will start to drop.

Other applications, such as xterm, do not generate the warning. I originally ran into the problem with an embedded java/SWT application that I am developing, but the problem shows up clearly with gedit.

Exiting ibus by running "ibus exit" allows gedit to receive input.

This worked until recently, so it appears to be a regression of some sort. It may be related to (https://bugzilla.redhat.com/show_bug.cgi?id=1004135) and, in fact, may already be fixed upstream in 1.5.4 (https://github.com/ibus/ibus/commit/98c7bdc5d92d5d2f25eb5f81fe90397664c2d435).

To repeat:

(1) Edit your ".vnc/xstartup" file to not create a normal session. A file that looks like this will do:
    #! /bin/bash -f

(2) Start a vnc server
    vncserver :10

(3) Start a vnc viewer
    vncviewer :10

(4) With IBUS running, start gedit in the VNC session:
    DISPLAY=:10 gedit

(5) Try to type into gedit... nothing will happen.

(6) Terminate the IBUS daemon
    ibus exit

(7) Try to type into gedit... you will see text.

(8) restart the ibus daemon
    ibus-daemon

(9) Try to type into gedit... nothing will happen.

-- Jim

ProblemType: Bug
DistroRelease: Ubuntu 13.10
Package: ibus 1.5.3-6ubuntu2
ProcVersionSignature: Ubuntu 3.11.0-14.21-generic 3.11.7
Uname: Linux 3.11.0-14-generic x86_64
NonfreeKernelModules: nvidia
ApportVersion: 2.12.5-0ubuntu2.1
Architecture: amd64
Date: Sun Dec 8 11:14:10 2013
InstallationDate: Installed on 2012-10-18 (415 days ago)
InstallationMedia: Ubuntu 12.10 "Quantal Quetzal" - Release amd64 (20121017.5)
MarkForUpload: True
SourcePackage: ibus
UpgradeStatus: Upgraded to saucy on 2013-10-29 (40 days ago)