libxcompshad3 software package provides NX shadowing library, you can install in your Ubuntu 14.04 LTS (Trusty Tahr) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install libxcompshad3
libxcompshad3 is installed in your system.
Make ensure the libxcompshad3 package were installed using the commands given below,
$ sudo dpkg-query -l | grep libxcompshad3 *
You will get with libxcompshad3 package name, version, architecture and description in a table
| Distro | Ubuntu 14 04 lts trusty tahr |
| Section | X Window System software |
| Package | libxcompshad3 |
| Version | 3.3.0-3-0ubuntu1 |
| Description | NX shadowing library |
| Sub Section | x11 |