Thank you for your reply.
In April 2012, this issue has been discussed with your staff. They promised to fix the problem in newer versions.
Wordpress is the latest version. Event Calendar, too.
If peerklyuchitsya on a standard theme, your plugin works.
I tried to install the English version of wordpress. The problem remained.
Disable all plugins. It does not help.
Increased memory for PHP. The problem remained.