When you install the Turn Off the Lights Firefox extension for the first time, you may see this yellow bar with the following text “a script in this extension is causing Firefox to slow down”.
Here the solution(s) on how to fix this issue in your Mozilla Firefox web browser:
Solution 1 – Firefox to slow down
Try to disable that one by one except Turn Off the Lights, that will fix this issue. Because some Firefox extensions block the loading of the Options page.
- Open the Firefox web browser
- Type this page in your address bar:
- And disable all the Firefox extensions one by one except “Turn Off the Lights”
If you can open well the Turn Off the Lights Options page, but you receive this yellow bar when enabling the “AutoStop” feature. Try to disable this option, because there is a bug in Mozilla Firefox performance of the Observer API.
The observer API does not work well on that Firefox web browser. However, there is no issue if you use the Google Chrome, Opera, Safari, and Microsoft Edge web browser.
If you still experience this error message “a script in this extension is causing Firefox to slow down”. Check you are using the Firefox version 65 or higher. Because this will show not this yellow bar anymore from Firefox.