Some pages like a Visualforce page uses iframes to display content. Spek icons may not appear in the iframe since it is a different URL from the main page. You must add the iframe URL to the Topic for Spek icons to appear.
To find the URL of an iframe:
Right-click inside of the Visualforce page or iframe
Click View Frame Source
In the Chrome address bar it will display something like this: view-source:https://www.w3schools.com/
Everything after "view-source:" is the URL of the iframe