editor: at init some preview pictures are shown twice

(from redmine: issue id 2048, created on 2015-01-12 by root, closed on 2015-01-16)

• Changesets:
  • Revision 1882 by Thorben Quast on 2015-01-16T15:18:03Z:

editor: some fixes in the previews (incl. fix #2048)

• Revision 1882 by Thorben Quast on 2015-01-16T15:18:03Z:

editor: some fixes in the previews (incl. fix #2048)