Fix issue #168 : Added support for switching between property page tabs with control-tab or control-shift_tab


git-svn-id: http://graph-studio-next.googlecode.com/svn/trunk@310 c2f33eb2-41b2-391d-4cb4-d9d0608729ba
Cosmetic code tidy up. No functional changes.

git-svn-id: http://graph-studio-next.googlecode.com/svn/trunk@311 c2f33eb2-41b2-391d-4cb4-d9d0608729ba