I do a lot of learning from a computer screen, on sites like hebrewbooks.org Sefaria and din online. I’ve heard that leaving a sefer open causes one to forget his learning. When I leave my computer screen to go to the bathroom or to get a coffee, can I leave my screen open or do I need to make it idle?
Although using a computer is a great tool to help a person learn, such as using Dinonline, Otzar Hachochma etc. nevertheless the computer screen, and the computer are not considered kadosh, and the screen doesn’t have the status of a sefer. If it did, you would not be allowed to close down or switch the screen if it had Hashem’s name on it, you would have to put your computer into genieza, and it would be an issue to take it into the bathroom. The reason all of these do not apply is because the words are only digital, and don’t really exist. Therefore they don’t have kedusha as if it is were a real sefer or a real shem Hashem.