I have no problems using jsroot in jupyter. I have no problems making plots in general in jupyter or jupyterlab. But when I use jsroot in python within JupyterLab; e.g.

import ROOT
%jsroot on
canvas = ROOT.TCanvas()
test = ROOT.TH1D("example","example",100,-5.,5.)
test.FillRandom("gaus",100000)
test.Draw()
canvas.Draw()

or in the ROOT C++ kernel, e.g.,

%jsroot on
TCanvas my_canvas("canvas","canvas title",800,600);
TH1D example("example","example histogram",100,-3,3);
example.FillRandom("gaus",10000);
example.Draw();
my_canvas.Draw();

I just see a blank area in the output that's the same size of the plot I expect. If I turn %jsroot off in both the above examples, the plot is produced. If I use the same notebooks in "plain old jupyter", the plots appear with %jsroot on.

I've tried this on two different machines/OSes with the same results:
OS - CentOS 7
Python version - 3.6.5
ROOT version - 6.14.02

OS - Mac OS 10.11.6
Python version - 3.6.6
ROOT version - 6.14.00

Any ideas?