When you open any odt file (can be empty) with libreoffice writer, the sidebar and panel do not do anything: there is no corresponding triangle next to the icon, and there are no close, minimize, maximize buttons. If I install lo-menubar package, there is no menu in the panel. Other file types (although I did not test all) work OK.
I am attaching a screenshot. You can see the lo-writer icon on the sidebar (which is set to be there) with no triangle, and the panel (global menu bar) shows the desktop (nautilus) menus (sorry it's not in english). If I maximize the lo-writer window, there are no close, minimize or maximize buttons, and the menu still belongs to the desktop.
Steps to reproduce:
1. open lo-writer
2. save the (empty or with some content) document as odt
3. open the just created file by double-clicking it
4. observe the sidebar and panel not working
This bug is also present in Unity 2D.