diff --git a/resources/vue/components/courseware/structural-element/CoursewareStructuralElement.vue b/resources/vue/components/courseware/structural-element/CoursewareStructuralElement.vue
index b4b38e175048cdbed4513a9c3fbc28b196d0342f..f2cb66baa97c66c03a8c9e32b6181cc55c89dec2 100644
--- a/resources/vue/components/courseware/structural-element/CoursewareStructuralElement.vue
+++ b/resources/vue/components/courseware/structural-element/CoursewareStructuralElement.vue
@@ -337,6 +337,7 @@
                                             <translate>Niveau</translate><br />
                                             <translate>von</translate>
                                             <select v-model="currentElement.attributes.payload.difficulty_start">
+                                                <option value="">-</option>
                                                 <option
                                                     v-for="difficulty_start in 12"
                                                     :key="difficulty_start"
@@ -347,6 +348,7 @@
                                             </select>
                                             <translate>bis</translate>
                                             <select v-model="currentElement.attributes.payload.difficulty_end">
+                                                <option value="">-</option>
                                                 <option
                                                     v-for="difficulty_end in 12"
                                                     :key="difficulty_end"
diff --git a/resources/vue/components/courseware/structural-element/CoursewareStructuralElementDialogAdd.vue b/resources/vue/components/courseware/structural-element/CoursewareStructuralElementDialogAdd.vue
index c34e45d7a1fdeaeb44845e0bd5b1fd4653a734a3..bdbfa944cf68b951c57ee081353e7484e49d91d9 100644
--- a/resources/vue/components/courseware/structural-element/CoursewareStructuralElementDialogAdd.vue
+++ b/resources/vue/components/courseware/structural-element/CoursewareStructuralElementDialogAdd.vue
@@ -131,12 +131,14 @@
                         {{ $gettext('Niveau') }}<br />
                         {{ $gettext('von') }}
                         <select v-model="difficulty_start">
+                            <option value="">-</option>
                             <option v-for="difficulty_start in 12" :key="difficulty_start" :value="difficulty_start">
                                 {{ difficulty_start }}
                             </option>
                         </select>
                         {{ $gettext('bis') }}
                         <select v-model="difficulty_end">
+                            <option value="">-</option>
                             <option v-for="difficulty_end in 12" :key="difficulty_end" :value="difficulty_end">
                                 {{ difficulty_end }}
                             </option>
diff --git a/resources/vue/components/courseware/unit/CoursewareShelfDialogAdd.vue b/resources/vue/components/courseware/unit/CoursewareShelfDialogAdd.vue
index a55d1e0555c63969328f365d8d4b5cd291636fe5..85379003a12e7f8ead524067f6fbcd7a585a11f4 100644
--- a/resources/vue/components/courseware/unit/CoursewareShelfDialogAdd.vue
+++ b/resources/vue/components/courseware/unit/CoursewareShelfDialogAdd.vue
@@ -118,6 +118,7 @@
                         {{ $gettext('Niveau') }}<br />
                         {{ $gettext('von') }}
                         <select v-model="addWizardData.difficulty_start">
+                            <option value="">-</option>
                             <option
                                 v-for="difficulty_start in 12"
                                 :key="difficulty_start"
@@ -128,6 +129,7 @@
                         </select>
                         {{ $gettext('bis') }}
                         <select v-model="addWizardData.difficulty_end">
+                            <option value="">-</option>
                             <option
                                 v-for="difficulty_end in 12"
                                 :key="difficulty_end"