Fix ?

js/src/tab.js

@@ -109,12 +109,13 @@ class Tab extends BaseComponent {
     this._activate(SelectorEngine.getElementFromSelector(element)) // Search and activate/show the proper section
 
     const complete = () => {
+      element.removeAttribute('tabindex')
+
       if (element.getAttribute('role') !== 'tab') {
         element.classList.add(CLASS_NAME_SHOW)
         return
       }
 
-      element.removeAttribute('tabindex')
       element.setAttribute('aria-selected', true)
       this._toggleDropDown(element, true)
       EventHandler.trigger(element, EVENT_SHOWN, {
@@ -136,13 +137,14 @@ class Tab extends BaseComponent {
     this._deactivate(SelectorEngine.getElementFromSelector(element)) // Search and deactivate the shown section too
 
     const complete = () => {
+      element.setAttribute('tabindex', '-1')
+
       if (element.getAttribute('role') !== 'tab') {
         element.classList.remove(CLASS_NAME_SHOW)
         return
       }
 
       element.setAttribute('aria-selected', false)
-      element.setAttribute('tabindex', '-1')
       this._toggleDropDown(element, false)
       EventHandler.trigger(element, EVENT_HIDDEN, { relatedTarget: relatedElem })
     }
@@ -162,6 +164,8 @@ class Tab extends BaseComponent {
 
     if (nextActiveElement) {
       nextActiveElement.focus({ preventScroll: true })
+      // eslint-disable-next-line no-console
+      console.log(nextActiveElement)
       Tab.getOrCreateInstance(nextActiveElement).show()
     }
   }
@@ -231,7 +235,6 @@ class Tab extends BaseComponent {
 
     toggle(SELECTOR_DROPDOWN_TOGGLE, CLASS_NAME_ACTIVE)
     toggle(SELECTOR_DROPDOWN_MENU, CLASS_NAME_SHOW)
-    outerElem.setAttribute('aria-expanded', open)
   }
 
   _setAttributeIfNotExists(element, attribute, value) {
@@ -285,6 +288,8 @@ EventHandler.on(document, EVENT_CLICK_DATA_API, SELECTOR_DATA_TOGGLE, function (
     return
   }
 
+  // eslint-disable-next-line no-console
+  console.log(this)
   Tab.getOrCreateInstance(this).show()
 })