- Set to open by default on insert.
- Updated selection handling not to always fully cascade to lowest
editable child on selection, so parents can be reliably selected.
- Updated mouse handling to treat details panes like the root element,
inserting within-details where relevant.
To provide more control of the summary as part of details.
To support, added a way to ignore elements during import DOM, allowing
up to read summaries when parsing details without duplicate nodes
involved.
