Cannot connect X window #3

I used this with jupyter docker-stacks datascience-notebook. I have added it successfully, and the kernel can run the gdl (0.9.7 from ubuntu 18.04). But when I want to plot, it needs plplot-xwin. After installing the plplot-driver-xwin, it says cannot connect to X window. As I see, the driver should be png, and I have installed the plplot-driver-cairo, but still the same error.
Why the GDL always use the xwin backends, is that related to the ubuntu version?
If so, could the gdl provide the binary for jupyter docker-stacks?
Many thanks.