htmlArticleGalley plugin ojs

Description of issue or problem I’m having:
The htmlArticleGalley plugin provied viewer only for articles and no issues.

	function register($category, $path, $mainContextId = null) {
		if (!parent::register($category, $path, $mainContextId)) return false;
		if ($this->getEnabled($mainContextId)) {
			HookRegistry::register('ArticleHandler::view::galley', array($this, 'articleViewCallback'), HOOK_SEQUENCE_LATE);
			HookRegistry::register('ArticleHandler::download', array($this, 'articleDownloadCallback'), HOOK_SEQUENCE_LATE);
		return true;

On the other hand epub and pdf plugin works for articles and issues as well.
Why is that happening?

Another thing I noticed for htmlArticleGally plugin is that in the viewer there is no download button so the only way to download an html article file is if the htmlarticlegally viewer plugin is not enabled.

Thank you