Plus sign to create a new tab has vanished

The addon is excellent however lately it has become very immune to any adware or website to take over and add itself as the home page url replacing the speeddial as home page by unticking the "add speeddial as my home page" option Also after i upgraded to Firefox version 53 the plus sign after the tab (to create a new tab) has vanished. This makes it extremely difficult to open a new tab and I had to install "Duplicate tab" addon to make a new tab. I hope the developer looks at comments and acts on it as soon as possible. Thanks