Re: I am fairly sure
"I have navigated trees with a + and - to collapse structures even in Linux apps. This is not "new", he had clearly got past the real changes i.e. having to start double clicking etc."
You could have read the article and realised that he was using the UNIX 'mail' application on a VT (aka dumb terminal) - likely a text only one... Some apps *did* run on VTs and offer the +/- idiom (ISTR trn did that) 'mail' most definitely did not.
Also note this guy was 'placid' - therefore it is extremely unlikely that he used a Windows box very often. Windows has a habit of making people permanently angry - compare and contrast Steve Ballmer with Dennis Ritchie for example.