@Dave - I know what you mean. Even apps notionally doing the same thing can differ markedly in the way they are used and in this instance I'd actually argue that it's AutoCAD's way of doing things that is peculiar (I'm not aware of other programs where you have to press Escape to unselect). It is a bit disappointing however to hear that Google don't seem to be interested in at least offering a customisation feature to disable Escape given how large a potential market AutoCAD users represent.
Thanks for the replies 😄 If there's anywhere to suggest new features I'll add my name to that one.