"Select" a ViewItem by referencing the ImageViewerAddOn it contains

ImageViewerAddOn addOn;

addOn.ViewItemIndex // can I use this to help reference the ViewItem I want to select?

How do I get the reference to the ViewItem??

Try the Smart Client View and Window Tool plugin sample, the Command tab, the Select Index button. I have an idea this is what you are looking for.

https://developer.milestonesys.com/s/article/Exploring-the-MIP-SDK-Tool-View-and-Window-Tool