diff --git a/CHANGELOG.md b/CHANGELOG.md
index 2a0d9fa..dc38eef 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,16 @@
 # Changelog
 
+## 3.1.1 (2026-10-08)
+
+### Fixed
+
+- Column mode no longer renders a literal `classnames="font-icon-plus"` HTML attribute on the copy
+  button. `classNames` is action-menu data, so it is now added in `getExtraData()` only; the menu
+  item keeps its plus icon (#6).
+- The stylesheet's `.dropdown-menu .gridfield-button-copy` rules are retired (commented out): the
+  admin's action menu never puts that class on a dropdown item on Silverstripe 5 or 6, so they never
+  applied. The menu item looks as before, with the admin's own plus icon like the core items (#6).
+
 ## 3.1.0 (2026-09-29)
 
 ### Added
diff --git a/code/GridField/CopyButton.php b/code/GridField/CopyButton.php
index 90a0fca..d8e1f59 100644
--- a/code/GridField/CopyButton.php
+++ b/code/GridField/CopyButton.php
@@ -132,7 +132,10 @@ private function getCopyAction($gridField, $record, $columnName)
             ['RecordID' => $record->ID]
         )
             ->addExtraClass('gridfield-button-copy')
-            ->setAttribute('classNames', 'font-icon-plus')
+            # `classNames` is action-menu data, not an HTML attribute: set here it also rendered as a
+            # literal classnames="..." attribute on the column button (#6). getExtraData() adds it
+            # to the menu data instead.
+            //->setAttribute('classNames', 'font-icon-plus')
             ->setAttribute('title', $title)
             ->setDescription(_t('GridAction.COPY_DESCRIPTION', 'Copy'))
             ->setAttribute('aria-label', $title);
@@ -253,7 +256,11 @@ public function getExtraData($gridField, $record, $columnName)
         $field = $this->getCopyAction($gridField, $record, $columnName);
 
         if ($field) {
-            return $field->getAttributes();
+            # The admin's React action menu builds the dropdown item's class from `action` plus this
+            # data's `classNames` only; the button's own `class` (gridfield-button-copy) never
+            # reaches it, on framework 5 or 6. font-icon-plus gives the item the admin's plus icon,
+            # as font-icon-edit/-trash do for the core items on framework 5.
+            return array_merge($field->getAttributes(), ['classNames' => 'font-icon-plus']);
         }
 
         return null;
diff --git a/css/GridFieldCopyButton.css b/css/GridFieldCopyButton.css
index efc8a03..f8b8b9a 100644
--- a/css/GridFieldCopyButton.css
+++ b/css/GridFieldCopyButton.css
@@ -26,10 +26,15 @@
 	-webkit-font-smoothing: antialiased;
 	-moz-osx-font-smoothing: grayscale;
 }
-.dropdown-menu .gridfield-button-copy:before {
-	content: "f";
-	margin-right: 2px;
-}
-.dropdown-menu .gridfield-button-copy:after {
-	content: attr(title);
-}
+/* Retired (#6): these never match on Silverstripe 4.13, 5 or 6. The admin's React action menu    */
+/* gives a dropdown item only `action` plus the menu data's classNames (font-icon-plus, see       */
+/* CopyButton::getExtraData()), never .gridfield-button-copy, so the menu item draws the admin's  */
+/* own plus icon and title text like the core items. Re-targeting these rules at the menu item    */
+/* would also pull in the column-button rules above (negative margins, min sizes).                */
+/* .dropdown-menu .gridfield-button-copy:before { */
+/* 	content: "f"; */
+/* 	margin-right: 2px; */
+/* } */
+/* .dropdown-menu .gridfield-button-copy:after { */
+/* 	content: attr(title); */
+/* } */
diff --git a/tests/CopyButtonTest.php b/tests/CopyButtonTest.php
index 0d89cbb..b0f9773 100644
--- a/tests/CopyButtonTest.php
+++ b/tests/CopyButtonTest.php
@@ -248,6 +248,23 @@ public function testColumnModeRendersTheCopyButtonForUsersWhoCanCreate()
         $this->assertNull($button->getExtraData($gridField, $record, 'Actions'));
     }
 
+    /**
+     * Regression for #6: up to 3.1.0 the column button carried a literal classnames="font-icon-plus"
+     * HTML attribute. `classNames` is menu data (the admin's React action menu reads it from
+     * getExtraData()), not an HTML attribute, and does nothing on a plain button.
+     */
+    public function testIssue6ColumnButtonHasNoLiteralClassNamesAttribute()
+    {
+        $this->logInWithPermission('ADMIN');
+        $button = new CopyButton(true);
+        $record = $this->objFromFixture(CopyRecord::class, 'first');
+
+        $html = (string) $button->getColumnContent($this->gridField($button, true), $record, 'Actions');
+
+        $this->assertStringContainsString('gridfield-button-copy', $html, 'control: the button rendered');
+        $this->assertDoesNotMatchRegularExpression('/\sclassnames=/i', $html);
+    }
+
     public function testColumnModeRendersNothingForUsersWhoCannotCreate()
     {
         $this->logOut();
@@ -275,6 +292,24 @@ public function testMenuModeOffersTheCopyItemForUsersWhoCanCreate()
         $this->assertArrayHasKey('data-url', $data);
     }
 
+    /**
+     * #6: the menu item's icon comes from the `classNames` menu data, which the admin's action menu
+     * puts on the dropdown item (framework 5 and 6 alike). Moving it off the column button must not
+     * lose it here.
+     */
+    public function testIssue6MenuItemKeepsItsIconClassInTheMenuData()
+    {
+        $this->logInWithPermission('ADMIN');
+        $button = new CopyButton();
+        $record = $this->objFromFixture(CopyRecord::class, 'first');
+
+        $data = $button->getExtraData($this->gridField($button, true), $record, 'Actions');
+
+        $this->assertIsArray($data);
+        $this->assertArrayHasKey('classNames', $data);
+        $this->assertContains('font-icon-plus', explode(' ', $data['classNames']));
+    }
+
     /**
      * Regression for the menu item being offered to users who cannot create (up to 2.0.1 it was shown
      * to everyone and refused only once clicked). A null group is what makes GridField_ActionMenu
diff --git a/tests/browser/specs/copy.spec.ts b/tests/browser/specs/copy.spec.ts
index 9995e82..131a492 100644
--- a/tests/browser/specs/copy.spec.ts
+++ b/tests/browser/specs/copy.spec.ts
@@ -124,3 +124,34 @@ test.describe('Column mode (CopyButton::create(true))', () => {
         await expect(locked.locator('.action-menu__toggle')).toBeVisible();
     });
 });
+
+test.describe('Icons and markup (#6)', () => {
+    test('the menu "Copy" item draws the admin plus icon like the core items, and no module rule restyles it', async ({ page }) => {
+        // The admin's React action menu puts only `action` + the menu data's classNames on a
+        // dropdown item (framework 5 and 6 alike), never the column button's `class`. The icon
+        // therefore comes from font-icon-plus in classNames, the admin's own icon class.
+        const grid = await openTab(page, 'menu');
+        const items = await openActionMenu(rowsTitled(grid, 'Menu copy').first());
+        const copy = items.filter({ hasText: /^Copy$/ });
+        await expect(copy).toHaveCount(1);
+        await expect(copy).toHaveClass(/(^|\s)font-icon-plus(\s|$)/);
+        const glyph = await copy.evaluate((el) => {
+            const before = getComputedStyle(el, '::before');
+            const after = getComputedStyle(el, '::after');
+            return { content: before.content, font: before.fontFamily, after: after.content };
+        });
+        expect(glyph.font.toLowerCase()).toContain('silverstripe');
+        expect(glyph.content).not.toBe('none');
+        // The pre-#6 stylesheet appended the title as ::after text inside the menu; nothing does now.
+        expect(glyph.after).toBe('none');
+    });
+
+    test('the column button carries no literal classnames attribute', async ({ page }) => {
+        // `classNames` is menu data for the React action menu, not an HTML attribute. Up to 3.1.0
+        // it was set on the column button too and rendered as classnames="font-icon-plus".
+        const grid = await openTab(page, 'column');
+        const button = copyColumnButton(rowsTitled(grid, 'Column copy').first());
+        await expect(button).toBeVisible();
+        expect(await button.getAttribute('classnames')).toBeNull();
+    });
+});