Install xfce4-wmdock-plugin by entering the following commands in the terminal:
sudo apt update sudo apt install xfce4-wmdock-plugin
Description:
Compatibility layer for running WindowMaker dockapps on Xfce
The WMdock plugin is a compatibility layer for running WindowMaker dockapps on the Xfce desktop. It integrates the dockapps into a panel, closely resembling the look and feel of the WindowMaker dock or clip, respectively.
Homepage: http://www.ibh.de/~ellguth/xfce4-wmdock-plugin.html
Version: 0.6.0-1build1
Section: universe/x11