Plugin Conflicts with Content Toolbar

I’ve the EXACT same problem. When I disable the plugin, the editor returns to normal functioning.

I have solved it comenting 2 lines in the file “useful-banner-manager.php”:

1. 1377: $plugin_array['usefulbannermanager'] = $useful_banner_manager_plugin_url . 'tinymce/useful-banner-manager.js';
2. 1413: add_action( 'wp_ajax_useful_banner_manager', 'useful_banner_manager_ajax_tinymce' );