--- a/devtools/client/inspector/inspector-search.js
+++ b/devtools/client/inspector/inspector-search.js
@@ -107,21 +107,19 @@ InspectorSearch.prototype = {
       this.searchBox.classList.add("devtools-style-searchbox-no-match");
       this.emit("search-result");
     }
   }),
 
   _onInput: function () {
     if (this.searchBox.value.length === 0) {
       this.searchClearButton.hidden = true;
-      this.searchBox.removeAttribute("filled");
       this._onSearch();
     } else {
       this.searchClearButton.hidden = false;
-      this.searchBox.setAttribute("filled", true);
     }
   },
 
   _onKeyDown: function (event) {
     if (event.keyCode === KeyCodes.DOM_VK_RETURN) {
       this._onSearch(event.shiftKey);
     }
 

--- a/devtools/client/themes/common.css
+++ b/devtools/client/themes/common.css
@@ -629,17 +629,16 @@ checkbox:-moz-focusring {
   padding-inline-end: 0;
 }
 
 .devtools-rule-searchbox {
   -moz-box-flex: 1;
   width: 100%;
 }
 
-.devtools-searchinput:-moz-any([filled],.filled),
 .devtools-filterinput:-moz-any([filled],.filled) {
   background-color: var(--searchbox-background-color);
   border-color: var(--searchbox-border-color);
 }
 
 .devtools-style-searchbox-no-match {
   background-color: var(--searcbox-no-match-background-color) !important;
   border-color: var(--searcbox-no-match-border-color) !important;