> You are completely right, there is a semantic difference. But I wonder
> if (have hard times believing) that this is recognizable by or even
> relevant to users.
In my opinion, this is recognizable whenever the user does to files
or folders something he does not do to launchers, like deleting or
dragging. I personally believe your points are valid in a context
where non-opening actions are very, very rare, and I don't think
this is the case. People rename and delete things all the time.
> > Plus, single-click for opening would make dragging less intuitive.
> > Firefox allows dragging of hyperlinked things, but I always hesitate
> > before dragging an hyperlinked element, wondering if I'll be able
> > to drag it without activating the link.
>
> Ok, don’t know how that would be handled, valid and very good point.
It's not like it *can't* be handled. For better or for worse,
Firefox does it. But I think it would hurt discoverability
of dragging.
> Yes, but in Google Docs you also open a document by single click.
Because its interface handles selection with checkboxes. That
solution cannot be ported to the desktop or any other interface
that is not list-based.
> Valid and true as well; but same thing as above, especially:
> »launchers […] are buttons […] do some
> > action, whereas icons represent […] "physical" objects.«
> Launchers are icons, that is the problem. Do users see a difference?
> Has it come up in usability tests?
"Users don't see a difference" sounds more like an argument
*against* single-click opening than *for* it. I don't know
if misleading the user into thinking two functionally
different elements are the same is a good idea.