I was able to reproduce this bug by removing the ubuntu dock from GNOME Shell 3.26.1 in distribution 17.10.
Please look at the method that docky for grabbing context from a gtk window
sudo apt-get remove gnome-shell-extension-ubuntu-dock sudo apt-get install docky
I was able to reproduce this bug by removing the ubuntu dock from GNOME Shell 3.26.1 in distribution 17.10.
Please look at the method that docky for grabbing context from a gtk window
sudo apt-get remove gnome-shell- extension- ubuntu- dock
sudo apt-get install docky