WordPress multisite with Piklist 0.9.9.11 (network activated) and a custom made plugin which creates custom taxonomy and custom post type (network activated as well). Whenever custom post type is either created or edited there’s an admin error saying:

Undefined index: order in "XXXXXX/wp-content/plugins/piklist/includes/class-piklist.php", line 2007

On a side note, there’s a clause at the line #2007 (class-piklist.php):

if( ! isset( $a[ 'args' ][ 'order' ] ) && ! isset ($b[ 'args' ][ 'order' ] ) )

… but somehow I think it should be:

if( ! isset( $a[ 'args' ][ 'order' ] ) || ! isset ($b[ 'args' ][ 'order' ] ) )

…because if either of these two evaluates true then the function itself returns error – an undefined index ‘order’.

Piklist welcome back, hopefully you live again but not as a zombie plugin 🙂