1. No drop-down menu
If the drop-down menu with Surfer Loading options is not appearing when you click on the extension icon:
make sure that you are clicking on the icon while on your Google Document page - otherwise, instead of the panel, a permissions & management window will appear
2. The sidebar is blank
If your sidebar loads but it's completely blank, the issue is most likely caused by the third-party cookies not being allowed in the browser.
Please check if those are enabled, and if not, follow the instructions that can be found here under Allow or Block cookies.
If you have just downloaded the extension and experienced problems, closing Chrome and opening it again might solve any issues you're facing. (It’s crazy how often turning it off and then on again works!).