diff --git a/extensions/chromium/preferences_schema.json b/extensions/chromium/preferences_schema.json
index f96578502..886cc87b4 100644
--- a/extensions/chromium/preferences_schema.json
+++ b/extensions/chromium/preferences_schema.json
@@ -94,10 +94,6 @@
       "description": "Whether to allow execution of active content (JavaScript) by PDF files.",
       "default": false
     },
-    "enableHighlightEditor": {
-      "type": "boolean",
-      "default": false
-    },
     "enableHighlightFloatingButton": {
       "type": "boolean",
       "default": false
diff --git a/web/app.js b/web/app.js
index d4d18516e..717f7c43b 100644
--- a/web/app.js
+++ b/web/app.js
@@ -543,11 +543,6 @@ const PDFViewerApplication = {
           typeof AbortSignal.any === "function") &&
         annotationEditorMode !== AnnotationEditorType.DISABLE
       ) {
-        const editorHighlightButton = appConfig.toolbar?.editorHighlightButton;
-        if (editorHighlightButton && AppOptions.get("enableHighlightEditor")) {
-          editorHighlightButton.hidden = false;
-        }
-
         this.annotationEditorParams = new AnnotationEditorParams(
           appConfig.annotationEditorParams,
           eventBus
diff --git a/web/app_options.js b/web/app_options.js
index 53c4b5325..3b70a4a1c 100644
--- a/web/app_options.js
+++ b/web/app_options.js
@@ -200,14 +200,6 @@ const defaultOptions = {
     value: true,
     kind: OptionKind.VIEWER + OptionKind.PREFERENCE + OptionKind.EVENT_DISPATCH,
   },
-  enableHighlightEditor: {
-    // We'll probably want to make some experiments before enabling this
-    // in Firefox release, but it has to be temporary.
-    // TODO: remove it when unnecessary.
-    /** @type {boolean} */
-    value: typeof PDFJSDev === "undefined" || PDFJSDev.test("TESTING"),
-    kind: OptionKind.VIEWER + OptionKind.PREFERENCE,
-  },
   enableHighlightFloatingButton: {
     // We'll probably want to make some experiments before enabling this
     // in Firefox release, but it has to be temporary.
diff --git a/web/viewer.html b/web/viewer.html
index d88391b80..7c31be103 100644
--- a/web/viewer.html
+++ b/web/viewer.html
@@ -363,7 +363,7 @@ See https://github.com/adobe-type-tools/cmap-resources
               </div>
               <div id="toolbarViewerRight">
                 <div id="editorModeButtons" class="splitToolbarButton toggled" role="radiogroup">
-                  <button id="editorHighlight" class="toolbarButton" type="button" hidden="true" disabled="disabled" title="Highlight" role="radio" aria-checked="false" aria-controls="editorHighlightParamsToolbar" tabindex="31" data-l10n-id="pdfjs-editor-highlight-button">
+                  <button id="editorHighlight" class="toolbarButton" type="button" disabled="disabled" title="Highlight" role="radio" aria-checked="false" aria-controls="editorHighlightParamsToolbar" tabindex="31" data-l10n-id="pdfjs-editor-highlight-button">
                     <span data-l10n-id="pdfjs-editor-highlight-button-label">Highlight</span>
                   </button>
                   <button id="editorFreeText" class="toolbarButton" type="button" disabled="disabled" title="Text" role="radio" aria-checked="false" aria-controls="editorFreeTextParamsToolbar" tabindex="32" data-l10n-id="pdfjs-editor-free-text-button">