Has anyone already managed a split of the screen in the view/ctp containing on the left side a list of items and on the right side details of a selected item?
Hox to address the data to the view, using iframe orr… ??
Yes i can help you out on manage split view
So you want of ajax load on left or in the iframe
Let me know
Iframes … 
Simplest but not most elegant solution:
In the view: create two html containers (DIVs or whatever)- pre-load list of items into left hand side container (set data in controller, pass to the view as usual), after each click on item trigger ajax call to some (can be same) action of the controller (pass id of item or whatever). The action could for an example output HTML or JSON, then in View inject returned html into container on right hand side or validate/parse JSON, fill template (for item preview) with JSON data and inject that into container.