When tabbing through the 'Page' tab in the Document Properties dialog I can't get past the 'Page Size' setting, because the focus is removed from there. I see a small flicker happen when changing the size, so I reckon the size change of the canvas happens in the background, but the focus isn't returned to the 'Page Size' list of options. This same thing happens when you change the 'Width' and want to tab to the 'Height': The canvas changes in the background, but the 'Height' field doesn't get focus. I haven't checked the other tabs, but it might happen there too I reckon.