ImageEn 5.2.0. The Print dialog Print Size combo box list lists "Specified size" twice. When you choose the first one, it fills the print preview to the page and allows you to choose the width and height, but they don't modify the size. And, when you select the second "Specified size," the width and height are disabled, so you can't modify the size.
I looked briefly at the source, and there's also something going on with non-English localizations on line 419 that might need to be looked at: