Missing content in post editor after upgrade to WP 3.5

Hi,
I just upgraded my local test environment to WordPress 3.5 and the content in the post editor was suddenly missing.

Following the instructions on wordpress.org I deactivated all plugins and activated one by one. The result from this was that only SAM causes the error.

I found a thread about JS causing the problem, but are not able to compare it with SAMs code. Maybe this thread can help someone to find the cause:
http://wordpress.org/support/topic/post-editor-missing-in-wp-35-after-upgrade

Thanks

http://wordpress.org/extend/plugins/simple-ads-manager/