Although page analysis and recognition are skew-tolerant, it may become difficult to window and OCR a page correctly when the skew is too significant.
Limited lineskew (less than 0.5°) can be ignored because the OCR accuracy does not suffer.
The option Page Deskewing (on the Options button) determines whether pages which were scanned at an angle will be deskewed, straightened automatically. (Limited lineskew is ignored.)
The command Deskew Page (on the image toolbar) straightens pages which were scanned at an angle. The page analysis gets re-executed afterwards.
Tip: don’t confuse with the detection of the page orientation - that routine corrects images that were scanned at a 90°, 180° or 270° angle!