The sidebar should still be visible by default, but no deck should be shown by default (only the tabbar should be visible).
We decided this in the Design chat.
Kendy, could you take over this task? I couldn't get this working.
Done now, just forgot to add the bug number to the commit message - sorry!
This bug fix comes with LibreOffice 4.4 (release notes https://wiki.documentfoundation.org/ReleaseNotes/4.4)
Sidebar open by default in Writer, Calc and Draw showing just the tab icons.