diff --git a/README.md b/README.md
index 09354f6..62103ab 100644
--- a/README.md
+++ b/README.md
@@ -41,6 +41,7 @@ If none of the tabs have `aria-selected=true`, then the first tab will be select
   <button type="button" id="tab-three" role="tab">Tab three</button>
   <!-- ... -->
 </tab-container>
+```
 
 ### Events
 
@@ -109,6 +110,7 @@ In those cases, apply `data-tab-container-no-tabstop` to the `tabpanel` element.
 ### Unmanaged slots
 
 `<tab-container>` aims to simplify complex markup away in the ShadowDOM, so that the HTML you end up writing is overall less. However sometimes it can be useful to have _full_ control over the markup. Each of the `::part` selectors are also `<slot>`s, this means you can take any part and slot it, overriding the built-in ShadowDOM.
+
 #### Unmanaged `tablist`
 
 You are able to provide your own `role=tablist` and `<tab-container>` will accommodate. This can be useful if you need extra presentational markup in the tablist. But remember:
@@ -148,6 +150,7 @@ You are able to slot the `tablist-tab-wrapper` part. This slot manages the tabs
   <div role="tabpanel"></div>
 </tab-container>
 ```
+
 #### Unmanaged `tablist-wrapper`
 
 If you want to take full control over the entire tab region, including managing the content before and after the tabs, then you can slot the `tablist-wrapper` element. Bear in mind if you're supplying this element that:
diff --git a/examples/index.html b/examples/index.html
index 12fc8e7..238e319 100644
--- a/examples/index.html
+++ b/examples/index.html
@@ -67,27 +67,6 @@ <h2>Horizontal (custom tablist and tablist-wrapper)</h2>
       </div>
     </tab-container>
 
-    <h2>Horizontal (custom tablist and tablist-tab-wrapper)</h2>
-
-    <tab-container>
-      <div slot="tablist-tab-wrapper">
-        <div role="tablist" aria-label="Horizontal Tabs Example">
-          <button type="button" id="tab-one" role="tab">Tab one</button>
-          <button type="button" id="tab-two" role="tab">Tab two</button>
-          <button type="button" id="tab-three" role="tab">Tab three</button>
-        </div>
-      </div>
-      <div role="tabpanel" aria-labelledby="tab-one">
-        Panel 1
-      </div>
-      <div role="tabpanel" aria-labelledby="tab-two" hidden>
-        Panel 2
-      </div>
-      <div role="tabpanel" aria-labelledby="tab-three" hidden>
-        Panel 3
-      </div>
-    </tab-container>
-
     <h2>Vertical (shadow tablist)</h2>
 
     <tab-container>
@@ -144,7 +123,7 @@ <h2>Set initially selected tab</h2>
 
     <h2>Set default tab</h2>
 
-    <tab-container default-tab-index="1">
+    <tab-container default-tab="1">
       <button type="button" id="tab-one" role="tab">Tab one</button>
       <button type="button" id="tab-two" role="tab">Tab two</button>
       <button type="button" id="tab-three" role="tab">Tab three</button>
diff --git a/src/tab-container-element.ts b/src/tab-container-element.ts
index 93e625a..ebccbd9 100644
--- a/src/tab-container-element.ts
+++ b/src/tab-container-element.ts
@@ -1,5 +1,20 @@
 const HTMLElement = globalThis.HTMLElement || (null as unknown as (typeof window)['HTMLElement'])
-const manualSlotsSupported = 'assign' in (globalThis.HTMLSlotElement?.prototype || {})
+
+// Function to see if manual slots are supported and if not, manual assign the slot attribute
+const assignSlotWithFallback =
+  'assign' in (globalThis.HTMLSlotElement?.prototype || {})
+    ? (slot: HTMLSlotElement, ...elements: Element[]) => {
+        slot.assign(...elements)
+      }
+    : (slot: HTMLSlotElement, ...elements: Element[]) => {
+        const host = (slot.getRootNode() as ShadowRoot).host
+        for (const element of host.querySelectorAll(`[slot="${slot.name}"]`)) {
+          element.removeAttribute('slot')
+        }
+        for (const element of elements) {
+          element.setAttribute('slot', slot.name)
+        }
+      }
 
 export class TabContainerChangeEvent extends Event {
   constructor(
@@ -95,7 +110,7 @@ export class TabContainerElement extends HTMLElement {
   static observedAttributes = ['vertical']
 
   get #tabList() {
-    const wrapper = this.querySelector('[slot=tablist-wrapper],[slot=tablist-tab-wrapper]')
+    const wrapper = this.querySelector('[slot=tablist-wrapper]')
     if (wrapper?.closest(this.tagName) === this) {
       return wrapper.querySelector('[role=tablist]') as HTMLElement
     }
@@ -112,7 +127,7 @@ export class TabContainerElement extends HTMLElement {
   }
 
   get #tabListTabWrapper() {
-    return this.shadowRoot!.querySelector<HTMLSlotElement>('slot[part="tablist-tab-wrapper"]')!
+    return this.shadowRoot!.querySelector<HTMLElement>('div[part="tablist-tab-wrapper"]')!
   }
 
   get #beforeTabsSlot() {
@@ -174,7 +189,7 @@ export class TabContainerElement extends HTMLElement {
     tabListContainer.style.display = 'flex'
     tabListContainer.setAttribute('part', 'tablist-wrapper')
     tabListContainer.setAttribute('name', 'tablist-wrapper')
-    const tabListTabWrapper = document.createElement('slot')
+    const tabListTabWrapper = document.createElement('div')
     tabListTabWrapper.setAttribute('part', 'tablist-tab-wrapper')
     tabListTabWrapper.setAttribute('name', 'tablist-tab-wrapper')
     const tabListSlot = document.createElement('slot')
@@ -184,7 +199,6 @@ export class TabContainerElement extends HTMLElement {
     const panelSlot = document.createElement('slot')
     panelSlot.setAttribute('part', 'panel')
     panelSlot.setAttribute('name', 'panel')
-    panelSlot.setAttribute('role', 'presentation')
     const beforeTabSlot = document.createElement('slot')
     beforeTabSlot.setAttribute('part', 'before-tabs')
     beforeTabSlot.setAttribute('name', 'before-tabs')
@@ -285,37 +299,15 @@ export class TabContainerElement extends HTMLElement {
     if (!this.#setupComplete) {
       const tabListSlot = this.#tabListSlot
       const tabListWrapper = this.#tabListWrapper
-      const tabListTabWrapper = this.#tabListTabWrapper
       const customTabList = this.querySelector('[role=tablist]')
       const customTabListWrapper = this.querySelector('[slot=tablist-wrapper]')
-      const customTabListTabWrapper = this.querySelector('[slot=tablist-tab-wrapper]')
       if (customTabListWrapper && customTabListWrapper.closest(this.tagName) === this) {
-        if (manualSlotsSupported) {
-          tabListWrapper.assign(customTabListWrapper)
-        } else {
-          customTabListWrapper.setAttribute('slot', 'tablist-wrapper')
-        }
-      } else if (customTabListTabWrapper && customTabListTabWrapper.closest(this.tagName) === this) {
-        if (manualSlotsSupported) {
-          tabListTabWrapper.assign(customTabListTabWrapper)
-        } else {
-          customTabListTabWrapper.setAttribute('slot', 'tablist-tab-wrapper')
-        }
+        assignSlotWithFallback(tabListWrapper, customTabListWrapper)
       } else if (customTabList && customTabList.closest(this.tagName) === this) {
-        if (manualSlotsSupported) {
-          tabListSlot.assign(customTabList)
-        } else {
-          customTabList.setAttribute('slot', 'tablist')
-        }
+        assignSlotWithFallback(tabListSlot, customTabList)
       } else {
         this.#tabListTabWrapper.role = 'tablist'
-        if (manualSlotsSupported) {
-          tabListSlot.assign(...[...this.children].filter(e => e.matches('[role=tab]')))
-        } else {
-          for (const e of this.children) {
-            if (e.matches('[role=tab]')) e.setAttribute('slot', 'tablist')
-          }
-        }
+        assignSlotWithFallback(tabListSlot, ...[...this.children].filter(e => e.matches('[role=tab]')))
       }
       const tabList = this.#tabList
       this.#reflectAttributeToShadow('aria-description', tabList)
@@ -330,11 +322,7 @@ export class TabContainerElement extends HTMLElement {
         const afterSlotted: Element[] = []
         let autoSlotted = beforeSlotted
         for (const child of this.children) {
-          if (
-            child.getAttribute('role') === 'tab' ||
-            child.getAttribute('role') === 'tablist' ||
-            child.getAttribute('slot') === 'tablist-tab-wrapper'
-          ) {
+          if (child.getAttribute('role') === 'tab' || child.getAttribute('role') === 'tablist') {
             autoSlotted = afterTabSlotted
             continue
           }
@@ -350,15 +338,9 @@ export class TabContainerElement extends HTMLElement {
             autoSlotted.push(child)
           }
         }
-        if (manualSlotsSupported) {
-          this.#beforeTabsSlot.assign(...beforeSlotted)
-          this.#afterTabsSlot.assign(...afterTabSlotted)
-          this.#afterPanelsSlot.assign(...afterSlotted)
-        } else {
-          for (const el of beforeSlotted) el.setAttribute('slot', 'before-tabs')
-          for (const el of afterTabSlotted) el.setAttribute('slot', 'after-tabs')
-          for (const el of afterSlotted) el.setAttribute('slot', 'after-panels')
-        }
+        assignSlotWithFallback(this.#beforeTabsSlot, ...beforeSlotted)
+        assignSlotWithFallback(this.#afterTabsSlot, ...afterTabSlotted)
+        assignSlotWithFallback(this.#afterPanelsSlot, ...afterSlotted)
       }
       const defaultTab = this.defaultTabIndex
       const defaultIndex = defaultTab >= 0 ? defaultTab : this.selectedTabIndex
@@ -401,18 +383,11 @@ export class TabContainerElement extends HTMLElement {
       if (!panel.hasAttribute('tabindex') && !panel.hasAttribute('data-tab-container-no-tabstop')) {
         panel.setAttribute('tabindex', '0')
       }
-      if (!manualSlotsSupported && panel.hasAttribute('slot')) {
-        panel.removeAttribute('slot')
-      }
     }
 
     selectedTab.setAttribute('aria-selected', 'true')
     selectedTab.setAttribute('tabindex', '0')
-    if (manualSlotsSupported) {
-      this.#panelSlot.assign(selectedPanel)
-    } else {
-      selectedPanel.setAttribute('slot', 'panel')
-    }
+    assignSlotWithFallback(this.#panelSlot, selectedPanel)
     selectedPanel.hidden = false
 
     if (this.#setupComplete) {
diff --git a/test/test.js b/test/test.js
index f5dce71..a65a03d 100644
--- a/test/test.js
+++ b/test/test.js
@@ -719,54 +719,4 @@ describe('tab-container', function () {
       assert.deepStrictEqual(panels.map(isHidden), [false, true, true], 'First panel is visible')
     })
   })
-
-  describe('with custom tablist-tab-wrapper', function () {
-    beforeEach(function () {
-      document.body.innerHTML = `
-      <tab-container>
-        <div slot="tablist-tab-wrapper">
-          <div role="tablist">
-            <button type="button" role="tab">Tab one</button>
-            <button type="button" role="tab" aria-selected="true">Tab two</button>
-            <button type="button" role="tab">Tab three</button>
-          </div>
-        </div>
-        <div role="tabpanel" hidden>
-          Panel 1
-        </div>
-        <div role="tabpanel">
-          Panel 2
-        </div>
-        <div role="tabpanel" hidden data-tab-container-no-tabstop>
-          Panel 3
-        </div>
-      </tab-container>
-      `
-      tabs = Array.from(document.querySelectorAll('button'))
-      panels = Array.from(document.querySelectorAll('[role="tabpanel"]'))
-    })
-
-    afterEach(function () {
-      // Check to make sure we still have accessible markup after the test finishes running.
-      expect(document.body).to.be.accessible()
-
-      document.body.innerHTML = ''
-    })
-
-    it('has accessible markup', function () {
-      expect(document.body).to.be.accessible()
-    })
-
-    it('the second tab is still selected', function () {
-      assert.deepStrictEqual(tabs.map(isSelected), [false, true, false], 'Second tab is selected')
-      assert.deepStrictEqual(panels.map(isHidden), [true, false, true], 'Second panel is visible')
-    })
-
-    it('selects the clicked tab', function () {
-      tabs[0].click()
-
-      assert.deepStrictEqual(tabs.map(isSelected), [true, false, false], 'First tab is selected')
-      assert.deepStrictEqual(panels.map(isHidden), [false, true, true], 'First panel is visible')
-    })
-  })
 })

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