1. A computing system, comprising: a pattern display component configured to display a hierarchical data structure that defines an arrangement of items on a user interface display, the hierarchical data structure having a set of nodes; a pattern selection component configured to display a pattern selection user input mechanism that is actuated to select a pattern and obtain a selected pattern; and a validation system configured to validate a selected portion of the hierarchical data structure against the selected pattern to identify whether the hierarchical data structure conforms to the selected pattern.