Admin Interface Add Button not displaying

In the admin area,
Suddenly, I notice that a lot of the "Add A Listing" , or "Add an Account" buttons are no longer displaying.
The gray left and right rounded corners are showing, but the actual text.

I thought maybe somehow the phrase got removed from the language database, however
An html inspection shows that there is an element defined style of "display: none important!;"
<span class="center_add" style="display: none !important;">Add an Account</span>

how did this start happening?

and how do I undo it?

Thanks for the help / advice

Maybe you replaced some texts by mistake, while working with an editor.
There is nothing to do that in admin panel.

Hello Tim,

I have opened your admin panel and I see all buttons.
https://www.screencast.com/t/PhvDAXSrev and https://www.screencast.com/t/HoAXs6la1u

Solution: For whatever reason... "Add" button was tagged as an "Ad" by the Ad Blocker software that comes by default with Opera... not sure why.. .possibly just the word "Ad" was flagged.

When I disabled ad blocker, it all worked fine. Happened suddenly because I recently updated Opera to new version with Ad-Blocker auto enabled.