Once in "artboard mode" (if you've resized using the artboard tool), you can no longer use "View Mode > Clip to Canvas" (the option is grey / unusable).
You'll have to delete all your artboards to see things outside of the canvas.
When deleting artboards, you get a dialog that allows you to keep your objects (phew) -- so just the artboard is deleted, and then you can use "View Mode > Clip to Canvas" again to see stuff outside the canvas.
Seems like after deleting artboard1 the canvas retains the dimensions of artboard1.
