May or may not be old info now, but wanted to add this in case others (like me) were searching google for a way to disable the annoying popups without disabling the entire plugin.
In Firefox look for a green 'a' (looks more like a swirl) in your top bars. Click it, this will bring onto the screen a rating box. At the bottom right is a box labeled 'Settings', click it. On the page that appears in the browser, look down for a checkbox with the text "Enable popups on search results page", uncheck it, click save, then either click the X on the ratings box or click anywhere outside of the box in the browser will close the ratings box.
The ability to disable the popups is in there, I don't know how long it has though, as I just recently updated the base program and have only been bothered by these annoying popups recently.
This software seems to be getting more and more intrusive every year. These browser popups were bad enough, but I had an avast registration popup knock me out of a full screen app and cause me to lose a couple of hours of work because of it. The application has some odd programing and compatibility issues with 64bit windows, and uses an overlay that when you alt-tab out or anything else (like this registration popup) knocks you out of the app, the screen is blank when you go back in. Result is you have to alt-tab back out and force kill the process and reload the program, causing you to lose any unsaved data to that point. This is starting to turn into another ZoneAlarm, just waiting for the day a software update makes the OS unbootable.