resurrect lost method in courseware tabs component, fixes #4975

Closes #4975

Merge request studip/studip!3734

resources/vue/components/courseware/layouts/CoursewareTabs.vue

@@ -76,6 +76,9 @@ export default {
                     break;
             }
         },
+        getActiveTabElement() {
+            return this.$refs['tabnav' + this.activeTab][0];
+        },
     },
     provide() {
         return {

resources/vue/components/courseware/structural-element/CoursewareRibbonToolbar.vue

@@ -85,7 +85,6 @@ export default {
             context: 'context',
             userById: 'users/byId',
             userId: 'userId',
-            selectedToolbarItem: 'selectedToolbarItem',
             currentElementisLink: 'currentElementisLink',
         }),
         isTeacher() {
@@ -107,7 +106,7 @@ export default {
             }
         },
         activate() {
-            const focusElement = this.$refs.tabs.getTabButtonByAlias(this.selectedToolbarItem);
+            const focusElement = this.$refs.tabs.getActiveTabElement();
             if (focusElement) {
                 this.initialFocusElement = focusElement;
                 this.trap = true;