You should always see a [[Pop-up blocker settings, exceptions and troubleshooting#w_what-are-pop-ups|banner at the top of the page]] when a popup window is blocked. Popups are allowed for certain user interaction events, as specified by '''dom.popup_allowed_events''' in [https://support.mozilla.org/en-US/kb/about-config-editor-firefox about:config]. Extensions may block popups without notice.

notification-message {
  --info-bar-background-color: #ffe900 !important;
  --info-bar-text-color: #0c0c0d!important;
}

Note that the background color of this notification bar is no longer yellow, so it is harder to notice this bar. In current releases you can add this CSS code to the <b>userChrome.css</b> file in the chrome folder in the Firefox profile folder. <hr> <pre><nowiki> notification-message { --info-bar-background-color: #ffe900 !important; --info-bar-text-color: #0c0c0d!important; }</nowiki></pre> <hr> It is not that difficult to create <b>userChrome.css</b> if you have never used it. The first step is to open the "Help -> Troubleshooting Information" page and find the button to access the profile folder with the random name (xxxxxxxx.default-release). *https://support.mozilla.org/en-US/kb/use-troubleshooting-information-page-fix-firefox You can find the button to go to the profile folder under the "Application Basics" section as "Profile Folder -> Open Folder". If you click this button then you open the profile folder in the Windows File Explorer. You need to create a folder with the name <u>chrome</u> in the profile folder with the random name (name is all lowercase). In the <b>chrome</b> folder you need to create a plain text file with the name <b>userChrome.css</b> (name is case sensitive). In this userChrome.css text file you paste the text posted. On Mac you can use the TextEdit utility to create the userChrome.css file as a plain text file. In Windows saving the file is usually the only time things get more complicated because Windows can silently add a .txt or .css file extension and you end up with a file like <i>userChrome.css.txt or userChrome.css.css</i>. To avoid this, you need to make sure to select "All files" in the "Save File" dialog in the text editor. You need to close (Quit/Exit) and restart Firefox when you create or modify the userChrome.css file. More info about userChrome.css/userContent.css in case you are not familiar: *https://www.userchrome.org/what-is-userchrome-css.html *https://www.userchrome.org/how-create-userchrome-css.html *https://www.userchrome.org/firefox-changes-userchrome-css.html In Firefox 69 and later you need to set this pref to true in about:config to enable userChrome.css and userContent.css. *about:config => toolkit.legacyUserProfileCustomizations.stylesheets => true *https://support.mozilla.org/en-US/kb/about-config-editor-firefox