Windows 7 type PIN TO PANEL window buttons, for XFCE - DockbarX. (Ubuntu)

https://github.com/TiZ-EX1/xfce4-dockbarx-plugin

sudo add-apt-repository ppa:xuzhen666/dockbarx 

sudo apt update

sudo apt install xfce4-dockbarx-plugin

Add dockbar from panel menu.