--- a/browser/base/content/browser.css
+++ b/browser/base/content/browser.css
@@ -606,22 +606,22 @@ html|input.urlbar-input[textoverflow]:no
   -moz-binding: url("chrome://browser/content/urlbarBindings.xml#urlbar-rich-result-popup");
 }
 
 #PopupAutoCompleteRichResult.showSearchSuggestionsNotification {
   transition: height 100ms;
 }
 
 #PopupAutoCompleteRichResult > deck[anonid="search-suggestions-notification"] {
-  visibility: collapse;
+  display: none;
   transition: margin-top 100ms;
 }
 
 #PopupAutoCompleteRichResult.showSearchSuggestionsNotification > deck[anonid="search-suggestions-notification"] {
-  visibility: visible;
+  display: -moz-deck;
 }
 
 #PopupAutoCompleteRichResult > richlistbox {
   transition: height 100ms;
 }
 
 #PopupAutoCompleteRichResult.showSearchSuggestionsNotification > richlistbox {
   transition: none;

--- a/browser/base/content/test/urlbar/browser_urlbarSearchSuggestions_opt-in.js
+++ b/browser/base/content/test/urlbar/browser_urlbarSearchSuggestions_opt-in.js
@@ -212,17 +212,18 @@ function suggestionsPresent() {
     }
   }
   return false;
 }
 
 function assertVisible(visible, win = window) {
   let style =
     win.getComputedStyle(win.gURLBar.popup.searchSuggestionsNotification);
-  Assert.equal(style.visibility, visible ? "visible" : "collapse");
+  let check = visible ? "notEqual" : "equal";
+  Assert[check](style.display, "none");
 }
 
 function promiseTransition(win = window) {
   return new Promise(resolve => {
     win.gURLBar.popup.addEventListener("transitionend", function() {
       // The urlbar needs to handle the transitionend first, but that happens
       // naturally since promises are resolved at the end of the current tick.
       resolve();

--- a/browser/base/content/test/urlbar/browser_urlbarSearchSuggestions_opt-out.js
+++ b/browser/base/content/test/urlbar/browser_urlbarSearchSuggestions_opt-out.js
@@ -117,14 +117,15 @@ function suggestionsPresent() {
     }
   }
   return false;
 }
 
 function assertVisible(visible, win = window) {
   let style =
     win.getComputedStyle(win.gURLBar.popup.searchSuggestionsNotification);
-  Assert.equal(style.visibility, visible ? "visible" : "collapse");
+  let check = visible ? "notEqual" : "equal";
+  Assert[check](style.display, "none");
 }
 function assertFooterVisible(visible, win = window) {
   let style = win.getComputedStyle(win.gURLBar.popup.footer);
   Assert.equal(style.visibility, visible ? "visible" : "collapse");
 }