You may encounter pages where AdBlock doesn't work the way you expect it to. When you click the AdBlock toolbar icon, most of the items that normally appear on the AdBlock menu are not there.
This happens because "internal" pages in all browsers, including Chrome, Firefox, and Edge, are not accessible to extensions. Internal pages include the New Tab page, the extensions manager, the browser's settings, and so on. Browsers don't allow extensions to inject code into these pages because these pages can change the way the browser behaves. Allowing extensions to possibly co-opt the browser would be a security risk.