If the CanvasSizeMode property is set to DevExpress.Diagram.Core.CanvasSizeMode.AutoSize, the canvas size is automatically expanded/shrunk to fit the current shape layout.
Initially, the canvas size equals the size of one page (the PageSize property).
When a shape is moved beyond the current canvas borders, the canvas is automatically expanded horizontally (by the PageSize.Width value) or vertically (by the PageSize.Height value).