[GNC] gnucash 3.6 -- reports -- "URL cannot be shown"

[Harry G McGavran Jr]

I compiled and installed gnucash 3.6 on Ubuntu Xenial
and works except Reports->Budget->Budget Profit and Loss
yields the proper display, but left clicking on a category
yields "URL cannot be shown".

I haven't yet found reports from other users on this.

How can I fix this???