The first link goes to a page about how Nodes can be designed.
Surrounding Content
It is common to surround interesting information with a border or other background.
Simple borders
Many of the simplest nodes just consist of a Panel of type Panel.Auto with a Shape surrounding a TextBlock.
But the content can be any arbitrarily complex Panel, not just a simple TextBlock.
My point is that you need to learn how to use Panels to organize the GraphObjects in your node template.