[Plugin: WP Calendar] TinyMCE Error

One possible fix is to change fsCalendarAdmin.php line 141:

// mod, see: https://core.trac.www.ads-software.com/ticket/18001
// add_action( 'admin_print_footer_scripts', 'wp_tiny_mce_preload_dialogs', 30 );
// change to:
add_action( 'admin_print_footer_scripts', 'wp_preload_dialogs', 30 );

But if you turn on DEBUG in wp-config.php, it turns out all this tiny_mce stuff is deprecated anyway. Here are the warnings. Only the second one is caused by my possible fix:

Notice: wp_tiny_mce is deprecated since version 3.3! Use wp_editor() instead.
Notice: wp_preload_dialogs is deprecated since version 3.3! Use wp_editor() instead.

See also: https://www.ads-software.com/support/topic/wp_tiny_mce-vs-wp_editor
https://www.ads-software.com/support/topic/wordpress-33-breaks-wp_tiny_mce

new version using new functions if they are available (backward compatibility!)