kwin-style-crystal software package provides semi transparent window decoration for KDE, 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 kwin-style-crystal
kwin-style-crystal is installed in your system.
Make ensure the kwin-style-crystal package were installed using the commands given below,
$ sudo dpkg-query -l | grep kwin-style-crystal *
You will get with kwin-style-crystal package name, version, architecture and description in a table
| Distro | Ubuntu 14 04 lts trusty tahr |
| Section | KDE |
| Package | kwin-style-crystal |
| Version | 2.2.1-2ubuntu1 |
| Description | semi transparent window decoration for KDE |
| Sub Section | KDE |