@Derwin Roland the query: (Predecessors.Project.ObjectID = <project oid>) or (Predecessors.Project.Name != "Another Project Name") would return features with predecessors in (or not in) a specific project.
In both of the instances above, you'll need to make sure that the app or widget itself is scoped appropriately so that it can access those items outside of the current project scope. Also, the downside to this is that you still may not be able to see the predecessor/successor relationship in the list.
If you are using Custom Views, check out the Cross Team Dependencies widget which will show all predecessors and successors with dependencies related to the project in scope.
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Kristy Corkan
Rally Product
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