If I understand correctly, you have one page with a ListView and a DataView on it. If so, there is a DataView somewhere on your page that is not set up to listen to the ListView. That DataView is the one that is expecting an object to be passed. If you could include a screenshot in your posting of the page in the Modeler, it would be helpful for troubleshooting.
The page in the screenshot works fine with the list on the left and main order data view on the right, I have other pages with orders in grids or lists that I want to select and go to the screenshot page with the order selected:
Not sure how to do this with a list view. Maybe others have ideas for that. I have a page like yours with a datagrid, but a template grid will also work: it has a feature 'select first'. You need to make sure that the list is ordered in a way the the object you want selected is first in the list.
I suspected that this is what you are trying to do. I have had this requirement as well and I could not fulfil it with the lists to widget.
Instead I opted to use a helper container entity instead:
Here is quick guide to get you started:
1. Create a new entity SelectionHelper with an association to one Order (call it SelectedOrder)
2. Put the SelectionHelper as apage parameter to your page. Wra both the listview and the dataview in it.
3. The dataview that is now listening to a widget should ber changed to take the value from Selectionhelper via SelectedOrded association.
4. On the list view change the behaviour to no selection. Add a triger for default action to be a single click. Add a hidden default button, that when clicked sets the SelectedOrder association on the SelectionHelper and refreshes the page.
Hope this helps,
PS: I almost forgot, to open a page with a preselected Order you need to set the association SelectedOrder before passing the SelectionHelper to the page.
Are you trying to open the page and have one Order selected and shown in the DataView atuomatically?
A screenshot would help us, help you :)