What is the use of being able to pick and drop 'f' into the Watch window, then, without the full expression 'a.f'?

I also don't really understand your explanation about why it doesn't work. If I pick 'a.f' in the Editor and then drop it into the Context tool, it correctly targets the Context tool: it doesn't stupidly ignore the 'a.' and throw up an error.

I realise that in the case of dropping 'a.f' into the Context tool we are talking about a class+feature, whereas in the case of dropping 'a.f' into the Watch window we are talking about an object+feature, so I can see why there may be a technical difficulty. But from the point of view of an end-user, it just seems inconsistent.

At the very least, dropping 'f' into the Watch window should not be allowed. The way it is now it just looks like a bug.