The present invention enables a three-pane page flow editor optimized for viewing and editing a page flow. It provides a visual representation of nodes/actions and the connections among them, enabling the ability to read and edit connections between nodes in a local area of the page flow without the overlaps between lines and crossovers once the page flow grows complex in real applications. In addition, it detects and resolves mismatches between annotations of a plurality of action outputs—representing data that an action can provide to a page, and a plurality of page inputs—representing data required by a page in the page flow. This description is not intended to be a complete description of, or limit the scope of, the invention. Other features, aspects, and objects of the invention can be obtained from a review of the specification, the figures, and the claims.