Academic approach to books on the screen - a problem?

Classroom use of books that are not books, but text on a computer screen
Recently I blamed students for not brining a text, and they pointed out that they had the text on theor laptop.
Can you read a book with critical awareness and analytic competence if you cannot move forwards and backwards in the same way as in a book? I can cross-reference and collate more easily in a book and thus get a sense of its overall shape and purpose. How does one find that other interesting spot if one has to scroll down or up whilst able to see only a bit at a  time?
Is this a matter of getting used to the format, or is there not a real problem here?
However that may be, the new form of reading resembles the process of listening in an oral culture.