I have the same bug too. It is a regression in 4.0
because it was always fine before that.
The print preview takes only 1/4 of the windows space reserved for it. The main view (were parts arrangement happens) looks fine, only the print preview is affected. Print preview can still be rotated and used normally. I think pribt preview should occupy the same space as main view.
I use Arch Linux, Nvidia card(prop. drivers), 4K monitor. Cinnamon DE, if it matters.
* If I resize the window with print preview on, then, while I am dragging it, the preview becomes normal size, occupying all available screen. However, as soon as I stop moving the mouse, preview becomes 1/4 of the size again.
* Switching graphics to legacy mode does not change anything visibly.
* Bug does not exist in version 3.1.1 on the same machine at the same time
Considering notes above, I am sure it has nothing to do with hardware or its drivers.