I am new with Cook Self Service. I created a one table component, built it and tried to run it in the sandbox. I got the error below:

Fatal error: Access to undeclared static property: plgSystemDemo::$activeViewLevels in /home/cook/sites/www.j-cook.net/public_html/sandbox/cms16/administrator/components/com_demo10737/demo10737.php on line 39

Since I am new to Joomla, PHP, etc., I do have a clue what this error means.

I have seen), it is a problem I need to fix.
It occurs when sandbox flushes.

Workaround :
You can use different than 1.6
1.7 is really similar.
3.2 is the best.

Fixed.