Cherry-pick 3 commits from master to 2.1 to fix Page Settings dialog layout

This comes out of #100221: Make Page Settings "Landscape" checkbox into proper "Portrait/Landscape" radio buttons. Red boxes in the screenshots following highlight areas to compare.

2.0.3, with single checkbox, no problems:

3.0-dev, with radio buttons and these commits from September 16 , no problems:

2.1-dev, with radio buttons but without those commits , problems: