是的，可以从tinyMCE中删除自定义颜色选项。

WordPress捆绑了一个tinyMCE插件来处理自定义颜色功能。这个tiny_mce_plugins 过滤器可用于删除此由键标识的捆绑插件colorpicker.

请注意，删除“自定义颜色”选项不会影响用户使用默认色样选择颜色的能力。

/**
 * Remove the Color Picker plugin from tinyMCE. This will
 * prevent users from adding custom colors. Note, the default color
 * palette is still available (and customizable by developers) via
 * textcolor_map using the tiny_mce_before_init hook.
 * 
 * @param array $plugins An array of default TinyMCE plugins.
 */
add_filter( \'tiny_mce_plugins\', \'wpse_tiny_mce_remove_custom_colors\' );
function wpse_tiny_mce_remove_custom_colors( $plugins ) {       

    foreach ( $plugins as $key => $plugin_name ) {
        if ( \'colorpicker\' === $plugin_name ) {
            unset( $plugins[ $key ] );
            return $plugins;            
        }
    }

    return $plugins;            
}