I've just upgraded to v2.0 of the plugin and am seeing error messages in the shortcode preview ("result") window. Everything was running fine with the old version, and this new version seems to work fine on the frontend, but just shows this error in the admin.
The error look something like this:
"Warning: call_user_func_array() expects parameter 1 to be a valid callback, function 'woocommerce_demo_store' not found or invalid function name in /home/mysite/public_html/wp-includes/plugin.php on line 406"
The same error message is shown below the preview of the shortcode (which looks fine) for all of the shortcodes I had created with the previous version of the plugin. I've also just tried to create a new shortcode and the same message is displayed in the preview pane even before any details are entered for the new element.