Currently, when the sidebar is taken from right side of
the screen to left side of the screen, the vertical tab
-bar is still attached towards the right side of deck.
Ideally, when the sidebar is attched towards the left
side of the screen, the tab-bar should automatically set
towards the left side of deck.

Change-Id: I1f56e5f0b7dfef37760e6563e7d757f7901cf2cd
Reviewed-on: https://gerrit.libreoffice.org/5979Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>