Tabs for relation

[SerhatReis]

It would be great if there was an option to display the relationship of an object in a separate tab, along with the associated data. For example, 'Order' with a tab for 'Order Lines.'

[pgarratt]

I second that, an ability to add custom pages as sub list from a main entity would be huge. could be used for all sorts of things.
Order - Order Lines, user - audit trail, product - product groups, company - related assets, etc..
Also helpful would be a way to open a specific sub item to view / edit the data.