root-level items trapped in root after first layer created

[Mental-users]

As things are currently, adding a layer to a document
that formerly had none will mean that any items at the
root level won't always be easily accessible.

Since we can't easily return to the root level anymore,
except by selecting individual items there (which won't
work for e.g. locked or hidden items), we need to deal
with the transition of a document that didn't have
layers into a layered document.

Probably the most straightforward approach would be,
when the user creates the first layer in the document,
create an extra bottom-most layer ("Background"?) and
move any root-level SPItems there. The resulting
document should behave more like users seem to expect.

We could even do this automatically on load, but this
kind of messing with the document structure is probably
better reserved to explicit actions by the user
(sometimes a flat document structure is important to
preserve).

[Axiomx11 (axiomx11)]

Originator: NO

I would like to second this request and suggest that all new documents
start with a layer (Layer 1?), and that we don't allow people to put shapes
in the quasi-layer of rootness which cannot be accessed/hidden/locked in
the layers dialog.

[Buliabyak-users (buliabyak-users)]

Originator: NO

But of course any new document is created with a layer which is made
current. That's in the new document template. This bug only applies to old
Inkscape documents (created before layers appeared in Inkscape) or to
non-Inkscape documents in which the user creates layers using Inkscape. So
it's pretty limited in scope.

[Peter Lewerin (vermeil-deactivatedaccount)]

I'm setting this to invalid as it shouldn't be an issue in typical use, and if it does occur, it can be fixed in the XML editor.