Thanks Nora, your explanation is quite clear! I got this from my textbook, but I agree it sounds weird.

Where did you read this sentence? Even as a Dutch person the second part to me sounds a bit strange. Could it be that you got this from a Belgian source, and that it is Flemish? Normally you would not say "die precies geen ideaal voor hen is geweest", because honestly it makes not much sense and to me even sounds wrong. Maybe someone else understands that part and can explain it.. But for what regards your question about "voor zich": "zich" reflects back to "iedere scholier", but the verb is not "zich voorhebben". Instead, it is: "voor zich hebben". This means something like: to have in front of you. So every student has had a professor in front of them/has found itself with a professor in front of the class, etc. You can use this expression in other situations too, like for example when you are on the phone with someone and you want to tell them something about a document you currently have open on your computer screen. You would say: "Ik heb hier een document voor me, en daarin staat ....". This is the first example that came up to me. Hope it's clear!