PlotWidget + TextItem + large range problem

[Geoffrey Cunningham]

Dear All,

I am developing an application in which graphs are embedded in a PyQt arrangement of Buttons, Widgets and the like, and am therefore using the PlotWidget method.  Mostly it is working fine, but when I encounter data with a large range, more than about 10^12 I think, then my TextItems disappear.  I attach a demonstration script based on the PlotWidget.py example. I am using PyQtgraph 0.10.0 with Python 3.6

Any suggestions gratefully received!

Geof