CTRL-space is a bad choice for shortcut as it is used by emacs

On what operating system?

OS (Linux distributions, UNIX or ...):Linux Mint 17
Architecture (i386, x86_64):x86_64
IBus version:1.5.5
Input method name and version:
Python version:2.7.6
dbus version:?
dbus-python version:?
gtk version (if bug is about gtk applications):
qt version (if bug is about qt applications):

What steps will reproduce the problem?

1. Install Linux Mint XFCE
2. Start emacs
3. Mark a block using CTRL-space
4. Get confused why CTRL-space does not work

1. Go to duolingo.com
2. Go to a listening lesson
3. Press CTRL-space to listen to the audio at a slower speed
4. Get confused why CTRL-space does not work

What is the expected output? What do you see instead?

I expect CTRL-space to be given to emacs/duolingo.

I see that CTRL-space is intercepted.

Please provide any additional information below.

According to the ibus people http://code.google.com/p/ibus/issues/detail?id=1732#c4 the default shortcut is Super+space.

Ubuntu uses a patch (debian/patches/ibus-xx-ctrl-space.patch) which changes the Super+space to CTRL+space.

That is a bad choice as CTRL+space is also used alot in Emacs. I have been unable to find the rationale behind overriding the default of Super+space, and thus I will suggest you simply remove the patch.

- o -

The problem is that I as a user am not told which program intercepts CTRL-space, so it is very hard for me to figure out which program eats my CTRL-space. ibus does not give a warning, and if you (like me) have a single input method engine installed, you do not see any change from pressing CTRL-space - making it even harder to figure out. I spent 2 frustrating hours figuring out what caused problem, and I expect other emacs/duolingo.com users will experience the same.

There are several ways in which this could be improved:

* Disable the shortcut if there is only one input method engine
* Give a pop-up dialog box the first time the user activates the shortcut, so that the user is aware that this shortcut is run by ibus and how to disable it if that is not what the user wants.
* Disable the shortcut by default - I would imagine the people that have the need for multiple input engines would have to select the input engines anyway, so they will see the preferences anyway and see that they can select a shortcut.

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: ibus 1.5.5-1ubuntu3
ProcVersionSignature: Ubuntu 3.13.0-32.57-lowlatency 3.13.11.4
Uname: Linux 3.13.0-32-lowlatency x86_64
ApportVersion: 2.14.1-0ubuntu3.2
Architecture: amd64
Date: Tue Jul 29 11:05:42 2014
InstallationDate: Installed on 2013-10-10 (291 days ago)
InstallationMedia: Linux Mint 15 "Olivia" - Release amd64 (20130520)
ProcEnviron:
 LANGUAGE=
 TERM=xterm
 PATH=(custom, no user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: ibus
UpgradeStatus: No upgrade log present (probably fresh install)