protected function getWyswigAllowedTags()
    {
        $allowedBecauseWysiwyg = [
            'div', 'p', 'br',  'pre', 'a',
            'h1', 'h2', 'h3', 'h4', 'h5', 'h6',
            'li', 'ul', 'ol',
            'strong', 'em', 'i', 'b',
        ];

        if ($this->isWysiwygEnabled('images')) {
            $allowedBecauseWysiwyg[] = 'img';
        }
        if ($this->isWysiwygEnabled('tables')) {
            $allowedBecauseWysiwyg = array_merge(
                $allowedBecauseWysiwyg,
                ['table', 'tbody', 'thead', 'tfoot', 'th', 'td', 'tr']
            );
        }
        if ($this->isWysiwygEnabled('fontcolor')) {
            $allowedBecauseWysiwyg[] = 'span';
        }
        if ($this->isWysiwygEnabled('subsuper')) {
            $allowedBecauseWysiwyg = array_merge(
                $allowedBecauseWysiwyg,
                ['sub', 'sup']
            );
        }
        if ($this->isWysiwygEnabled('underline')) {
            $allowedBecauseWysiwyg[] = 'u';
        }
        if ($this->isWysiwygEnabled('embed')) {
            // Note: Only <iframe>. Not <script>, <embed> or <object>.
            $allowedBecauseWysiwyg[] = 'iframe';
            // We also need to add a few attributes as well.
            $this->setAllowedAttributes(array_unique(array_merge(
                    $this->getAllowedAttributes(),
                    ['src', 'width', 'height', 'frameborder', 'allowfullscreen', 'scrolling']))
            );
        }
        if ($this->isWysiwygEnabled('ruler')) {
            $allowedBecauseWysiwyg[] = 'hr';
        }
        if ($this->isWysiwygEnabled('strike')) {
            $allowedBecauseWysiwyg[] = 's';
        }
        if ($this->isWysiwygEnabled('blockquote')) {
            $allowedBecauseWysiwyg[] = 'blockquote';
        }
        if ($this->isWysiwygEnabled('codesnippet')) {
            $allowedBecauseWysiwyg = array_merge(
                $allowedBecauseWysiwyg,
                ['code', 'pre', 'tt']
            );
        }

        return array_unique(array_merge($this->getAllowedTags(), $allowedBecauseWysiwyg));
    }