An editor opens a page in the Page Editor. She works with some personalized components on the page. At the end of the editing session, the page can be in a mixed state where some personalized components render the original content while others render a variant. As the editor transitions from editing to previewing the page, personalized components should render the same content they did in the edit mode. Don't switch components back to their original content for preview because that would confuse the editor.

This behavior is identical to how previewing a page with variants works: the variant you last had open in the edit mode is also rendered in the preview.