Canvas size problem
 

(5.1 b4)
Having some difficulty getting OG to accept a simple A3 landscape canvas size - it keeps showing me a canvas that is twice as wide as and twice as deep (only with lines indicating the position of the A3 page).
For some reason OG is increasing the canvas to include everything on it despite specifying "A3" in the Page Settings.
I have used A3 canvases before without a problem, so I tried to think what was different this time around - apart from the use of beta 4.
There are a number of objects that span to "off-canvas" - but I am sure this has worked OK before.
I have also tried various combinations of the settings under the Inspector/ Canvas Size but these don't force a single landscape A3 canvas either. In fact, it reverts back to 2 pages x 2 pages or the equivalent size in cm to include all objects.
Is this a user error?
stax