Fix a few problem in Ubuntu/Xubuntu 18.04 Bionic LTS mouse speed, no Internet, no local network, Cairo Dock. 

To start ALWAYS HAVE A BACK-UP OF EVERYTHING YOU EDIT, CHANGE OR ADD.
I use bootable DVD's or USB drives with Paragon Hard Drive Manager 15, Other Linux OS's running live from a DVD or USB.
For me Paragon is the best they only make it for Windows but you can boot to a USB or DVD and make system images of your Linux installs.
With a system image if anything goes wrong you can just restore the working image!

These are a few of the fixes I have had to use with Xubuntu/Ubuntu 18.04.2 "Bionic". The original 18.04 release was just really bad so I have been
trying each new one Xubuntu/Ubuntu 18.04, 18.04.1 and now 18.04.2 this one is close enough to make it run better than 16.04.2.

Note:
In 18.04 the apt-get has changed to just "apt" but apt-get still works. So if you use just "apt" and it does not work switch to "apt-get"

Mouse Speed
To fix your mouse if it's running at lightning speeds in Xubuntu/Ubuntu 18.04. This normally only happens if you have a high DPI mouse 5000 or higher.

1. Type or copy and paste these one at a time into a terminal window and hit enter after each one.
xinput list
xinput list-props (DEVICE ID)
xinput set-prop 8 297 -0.3
Note you need to change the 8 with your mouse ID, and the 294 with your "Accel Speed" property number.
I'm using -0.3 you might want to set it to something different (-0.8, -0.6, -0.5) .

2. To make this change permanent after reboot, you will need to set that command to run automatically at startup.
In Xubuntu you have a menu go to Settings -> Session and Startup -> Application Autostart -> Add (no menu use search)
And then fill in the full xinput command in the command and a name and description. "xinput set-prop 8 297 -0.3"

No Internet or Local Network
If the internet or local network are not working in Xubuntu/Ubuntu 18.04. This is an instant fix there is a permanent fix listed below.
Type or copy and paste this into a terminal window and hit enter.
sudo /etc/init.d/dnsmasq restart (This is an instant fix to get you online and local network working)

1. Then type or copy and paste these into a terminal window one at a time and hit enter after each one.
sudo apt-get remove dnsmasq-base
sudo apt-get install dnsmasq
sudo apt-get update

2. Open and edit the dnsmasq config file. (use the editor you like I like nano)
sudo nano /etc/dnsmasq.conf OR sudo vim /etc/dnsmasq.conf 

3. Add these lines:
interface=lo
bind-interfaces
listen-address=127.0.0.1

If the network manager has a dnsmasq line remove it.

4. Restart the NetworkManager
sudo /etc/init.d/network-manager restart

5. Restart dnsmasq
sudo /etc/init.d/dnsmasq restart

6. ONLY IF NEEDED fix error "Unknown error: /usr/lib/x86_64-linux-gnu/libgtk3-nocsd.so.0" (also fixes no network problems)
sudo apt install gtk3-nocsd
sudo apt install libgtk3-nocsd0:i386

Cairo Dock
Install Cairo Dock on Xubuntu/Ubuntu 18.04 or fix Cairo Dock if you upgraded from Xubuntu/Ubuntu 16.04.
1. Add Key:
Type or copy and paste this into a terminal window and hit enter.
wget -q http://download.tuxfamily.org/glxdock/repository/cairo-dock.gpg -O- | sudo apt-key add -

2. Edit your sources list
Type or copy and paste this into a terminal window and hit enter. (use the editor you like I like nano)
sudo nano /etc/apt/sources.list OR sudo gedit /etc/apt/sources.list

3. Type or copy and paste this into a terminal window and hit enter:
deb http://download.tuxfamily.org/glxdock/repository/ubuntu (bionic) cairo-dock
18.04 should look like this: deb http://download.tuxfamily.org/glxdock/repository/ubuntu (bionic) cairo-dock

4. If you had Cairo Dock installed in 14.04 or 16.04 be sure to run this. New install skip to "5"
Type or copy and paste this into a terminal window and hit enter.
sudo apt-get remove cairo-dock* --purge

5. If this is the first install or you just removed the old Cairo Dock.
Type or copy and paste these into a terminal window one at a time and hit enter after each one.
sudo apt-get update
sudo apt-get install cairo-dock
sudo apt-get install cairo-dock cairo-dock-plug-ins

6. Start Cairo Dock on system boot.
On the menu (Xubuntu) under settings if you don't have a menu use the search.
Sessions and Startup
Application Autostart
Add (bottom left)
Name: Cairo Dock
Command: cairo-dock -o (with open-gl)

Any questions just ask.
This post was edited by beastusa at July 29, 2019 12:45 PM PDT

Always keep this in your terminal "sudo /etc/init.d/dnsmasq restart"

Any time your internet is not working just run that command and it should fix it.