How to make zOrder work?

I have a nodeTemplate and a linkTemplate .NodeTemplate include a go.Picture and a go.TextBlock,I want nodeTemplate on top of linkTemplate. So I set nodeTemplate’s zOrder in 2,and linkTemplate’s zOrder in 1. But as a result, the textBlock of nodeTemplate is always in the lower level of the line. How can I make zOrder work? Is there any other method to solve this situation?

First, have you read https://gojs.net/latest/intro/layers.html ?
It is unusual to use the Part.zOrder property.

Second, do you have a small screenshot showing the situation and either a description or annotation showing what you want to be different?

Thank you so much about the link,I find where the problem is.