Why is the areas detection button hidden for some outputs?

[trespda]

When the output is set to hocr/pdf, area detection (auto and manual adjustment) is disabled (hidden). Why is that really? How does the output depend on it?

[manisandro]

This is expected - in hOCR mode, the layout detection is performed automatically and indeed the resulting document tree is based on the layout detection. Currently, hOCR will always process the entire page.