ctrl+shift will window snapping the focused window to the bottom half.

[Jiawen Chen]

Ctrl + shift alone will snap the window, so it collides many other shortcuts of the form ctrl + shift + <key>.
The issue can be solved by disabling window snapping in unity-tweak-tool.
Note: Some of the windows cannot be snapped. So try it on different windows.

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: unity 7.2.6+14.04.20151021-0ubuntu1
ProcVersionSignature: Ubuntu 3.13.0-74.118-generic 3.13.11-ckt30
Uname: Linux 3.13.0-74-generic x86_64
NonfreeKernelModules: nvidia
ApportVersion: 2.14.1-0ubuntu3.19
Architecture: amd64
CompizPlugins: No value set for `/apps/compiz-1/general/screen0/options/active_plugins'
CurrentDesktop: Unity
Date: Mon Jan 11 01:30:00 2016
InstallationDate: Installed on 2016-01-06 (4 days ago)
InstallationMedia: Ubuntu 14.04.1 LTS "Trusty Tahr" - Release amd64 (20140722.2)
SourcePackage: unity
UpgradeStatus: No upgrade log present (probably fresh install)