fix #2088

Closes #2088

Merge request studip/studip!1361

resources/assets/stylesheets/scss/courseware.scss

@@ -1366,20 +1366,6 @@ label[for="cw-keypoint-color"] {
                                 }
                             }
                         }
-                        @each $type, $icon in $element-icons {
-                            &.cw-tree-item-#{$type} .cw-tree-item-wrapper a.cw-tree-item-link {
-                                 background-position: 0px 2px;
-                                 background-repeat: no-repeat;
-                                 padding-left: 20px;
-                                 @include background-icon(#{$icon}, clickable, 16);
-                                 &:hover {
-                                     @include background-icon(#{$icon}, attention, 16);
-                                 }
-                                 &.cw-tree-item-link-current {
-                                     @include background-icon(#{$icon}, info, 16);
-                                 }
-                             }
-                         }
                         ol {
                             padding-left: 0.25em;
                             &.cw-tree-draggable-list {

resources/vue/components/courseware/CoursewareTreeItem.vue

@@ -2,9 +2,6 @@
     <li v-if="showItem"
         :draggable="editMode ? true : null"
         :aria-selected="editMode ? keyboardSelected : null"
-        :class="[
-                hasPurposeClass ? 'cw-tree-item-' + purposeClass : '',
-            ]"
     >
         <div class="cw-tree-item-wrapper">
             <span