lxappearance software package provides LXDE GTK+ theme switcher, 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 lxappearance
lxappearance is installed in your system.
Make ensure the lxappearance package were installed using the commands given below,
$ sudo dpkg-query -l | grep lxappearance *
You will get with lxappearance package name, version, architecture and description in a table
| Distro | Ubuntu 14 04 lts trusty tahr |
| Section | Utilities |
| Package | lxappearance |
| Version | 0.5.5-1 |
| Description | LXDE GTK+ theme switcher |
| Sub Section | Utils |