Methods and systems providing a user interface control allowing a user to specify a scope of items on a computer system or network is disclosed. Certain aspects provide an input control through which a user can specify an explicit scope, or range, of items, while also identifying explicit exclusions from the specified scope, thereby reducing ambiguity regarding identification of items included and items excluded from the scope. When a user explicitly selects an item for inclusion in the scope, the explicitly selected item is added to the scope definition, and all descendants of the explicitly selected item are implicitly selected for inclusion. When a user explicitly selects an item for exclusion from the scope, the explicitly selected item is added to the scope definition as an exclusion from an explicitly included item, and all descendants of the explicitly selected item are implicitly selected for exclusion.