Docky, like Plank or Cairo Dock, is an advanced shortcut bar that sits at the edges of your screen. It provides easy access to some of the files, folders and applications on your computer, displays which applications are currently running, holds windows in their minimized state and more.
sudo add-apt-repository ppa:docky-core/stable sudo apt-get update sudo apt-get install docky
sudo apt-get remove --purge docky && sudo apt-get autoclean && sudo apt-get autoremove
Optional: Delete Docky PPAs and Authentication key in Software Sources
It happens that System Settings icon is incorrectly displayed as “Bluetooth” in Docky for Linux Mint users (at least in the Cinnamon edition).
Next, I’ll give you some tips on how to correct this visually odd glitch. Hopefully it will help you not only with the System Settings icon but with any other application icon wrongfully represented in Docky. Let’s get down to it 
Straight to the point
In Terminal:
sudo killall docky sudo cp /usr/share/applications/cinnamon-settings.desktop /usr/share/applications/cinnamon-settings.desktop.`date +"%m_%d_%Y"` sudo sed '/Keywords=/a\StartupWMClass=Cinnamon-settings.py' -i /usr/share/applications/cinnamon-settings.desktop rm ~/.cache/docky/docky.desktop.*.cache
Now launch docky once again and enjoy your System Settings icon
What was done
1- Close Docky:
sudo killall docky
2- Make a backup copy of /usr/share/applications/cinnamon-settings.desktop. This is the file we worked with.
sudo cp /usr/share/applications/cinnamon-settings.desktop /usr/share/applications/cinnamon-settings.desktop.`date +"%m_%d_%Y"`
…and make sure the backup copy is there 😉
ls -la /usr/share/applications/cinnamon-settings.desktop* $-rw-r--r-- 1 root root 11022 Jan 8 08:36 /usr/share/applications/cinnamon-settings.desktop $-rw-r--r-- 1 root root 11022 Jan 8 08:40 /usr/share/applications/cinnamon-settings.desktop.01_08_2016
3- Edited cinnamon-settings.desktop adding StartupWMClass=Cinnamon-settings.py attribute so that Docky can match its icon.
sudo gedit /usr/share/applications/cinnamon-settings.desktop
4- Clear current user Docky cache
rm ~/.cache/docky/docky.desktop.*.cache
That’s all!
Fixing Docky Icons
If you ever come across an icon in Docky not being properly displayed, here is a way to correct it.
1- Get the WM_CLASS property from the application window. In Terminal:
xprop | grep WM_CLASS | awk '{print $4}'
Press < 'Enter'> and click the window you want to get the WM_CLASS from. Take note of the output
For example, System Settings WM_CLASS is “Cinnamon-settings.py” (see screenshot above), which is the value we used as StartupWMClass attribute, as explained in step #3.
2- Edit its corresponding .desktop file under /usr/share/applications as we did with cinnamon-settings.desktop.
3- Close Docky, delete its cache files and launch it again.
Your comment is appreciated. Let me know if this helped you in some way!
