Updated V 5.0.9 Aug 9 2014
inc/_core/_template.funcs.php (@version $Id: _template.funcs.php 4638 2013-09-05 06:46:32Z yura $
line 1844 and 1854 amended to NULL to avoid HTML5 verification failure

Updated V 5.0.6 Jan 22nd 2014
line 1844 as below

inc/_core/_template.funcs.php ( @version $Id: _template.funcs.php 4233 2013-07-16 10:12:35Z attila $)
line 1813 was [ 'form_action' => '',]
now: [ 'form_action' => NULL,]
reason: to remove validation error of empty action
Null produces blog root e.g. elf.php