fixes #316
closes #433

commit 6d9584caf54e0655c8c67375bc622dc3e38c2c28
Author: Don Syme <donsyme@fastmail.fm>
Date:   Sat May 9 18:14:42 2015 +0100

    fix 316

commit da567164f7c5d79119c13f5f5c2373b0dedd77d3
Author: Don Syme <donsyme@fastmail.fm>
Date:   Sat May 9 17:45:54 2015 +0100

    Fix 316