So, basically, what the parameters do:
1) focusNodeExpansionRadius - how many levels to automatically open upon the load (or when you add new focus nodes by right click)
2) numberOfFocusNodes: max number of focus nodes in chart
3) focusNodeTailExpansionRadius - Number of "levels" to automatically expand around the most recently focused node. If set to 1, all nodes directly linked to the focused node will be shown. If set to 2, all nodes directly connected to these nodes will be shown as well. Etc. Also used for calculating node relevance.
I created a basic example on top of big data sample:
And this looks fine - it opens 5 levels on initial load and if I focus any of the other nodes, behaviour looks fine.
Can you try this basic example? If it works, perhaps there is an issue with Vue integration with ZC.