sometimes not all the links are highlighted
For instance in gmail, the items on top horizontal (back to drafts, mark as unread, snooze, etc) aren't able to be clicked
Some times buttons and links are not implemented following the web standards. In this case the extension will not identify them properly.
I can't find the links you mention as examples, in gmail I only see icons instead of links
Could you bring more details or a picture of them so I can check why the extension doesn't highlight them?