I subscribe to ClientControl.NewImageViewerControlHandler event. I need to know for which "sub view " of the ViewAndLayoutItem the event was fired. I need to know the layout index. How do get this information from the ImageViewerAddOn object?
Maybe, you could use MessageId.SmartClient.SelectedViewItemChangedIndication instead and can be tested with the messagetester sample - https://doc.developer.milestonesys.com/html/index.html?base=samples/pluginsamples/messagetester/readme.html&tree=tree_1.html