12.04gnomegnome-tweak-tool
How do I fix this? I will attempt to upload a screenshot of the problem. Notice there is an error like triangle near the shell themes and nothing is select-able. Also there are no shell extensions under the shell extensions tab. I have come across many postings on how to fix this but none worked for me. I currently have 12.04 LTS. I have a custom Phenom quad core machine with Radeon HD 5770 graphics if that helps.
When you download a theme for Ubuntu this come compressed into a .tar.gz file almost always. What you have to do is:
cd ~ && mkdir .themes.themes folder in your personal folder. The dot is necessarycp files_path ~/.themesfiles_path with the directory where are your zipped files. This command copy the compressed files into this folder.cd ~/.themes && tar xvzf PACKAGENAME.tar.gzPACKAGENAME with the name of the file. This command will unzip the theme file into the new folder.gnome-tweak-toolFinally will appears the tweak window (similar as the following) and you'll see the themes that you've previously copy in the themes folder and will be able to choice them!
For future themes, omit the second step
Similar question here
Howto:
Add the official Gnome Shell Extensions ppa:
sudo add-apt-repository ppa:webupd8team/gnome3
sudo apt-get update
Install dependencies:
sudo apt-get install gnome-shell-extensions
sudo apt-get install gnome-shell-extensions-common
Afterwards, enabling on the link provided works fine.
Best Answer
If you are using gnome-classic session, You can't enable shell theme, simply because you aren't using gnome-shell.
Login to Gnome session, which uses Gnome-Shell. Install the user-theme extension by going to this page. Close the gnome-tweak-tool and re-open it. You should now change the gnome-shell theme
You should also install gnome-shell themes to be able to select a custom theme than the default one.
See this question: How do I get and install more themes, icons, and pointers?