This is a Document Preference. It controls the linking of the Sheet Borders to the…
Vectorworks Tip #115 – Basic Tools – Ortho drawing in Vectorworks
Some users want to be able to draw orthographically (constrained to 0, 90). I usually get this request from AutoCAD users. Hold down the Shift key to constrain linear objects (walls, lines, polygons) to orthographic and other objects (rectangles, ovals) to symmetric.