Text blinks on selection with <Ctrl+Shift+arrow> if keyboard layout switcher is <Ctrl+Shift>

[Norbert]

Steps to reproduce:
1. Install Ubuntu 16.04.
2. Launch Unity session.
3. Set <Ctrl+Shift> as keyboard layout switcher in unity-control-center.
4. Try to select text with <Ctrl+Shift+left> or <Ctrl+Shift+right> in text field or textarea (for example in Firefox).

Expected results:
* Text is selected without blinks and other visual effects.

Actual results:
* Text is selected, but it blinks.

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: indicator-keyboard 0.0.0+16.04.20151125-0ubuntu1
ProcVersionSignature: Ubuntu 4.4.0-75.96-generic 4.4.59
Uname: Linux 4.4.0-75-generic x86_64
ApportVersion: 2.20.1-0ubuntu2.5
Architecture: amd64
CurrentDesktop: Unity
Date: Tue May 2 12:38:59 2017
InstallationDate: Installed on 2014-02-07 (1179 days ago)
InstallationMedia: Ubuntu 12.04.4 LTS "Precise Pangolin" - Release amd64 (20140204)
SourcePackage: indicator-keyboard
UpgradeStatus: Upgraded to xenial on 2017-04-15 (16 days ago)
upstart.indicator-keyboard.log: (unity-control-center:32705): Gtk-CRITICAL **: gtk_notebook_set_current_page: assertion 'GTK_IS_NOTEBOOK (notebook)' failed