diff --git a/frontend/src/components/AdminConfigValueEditor.vue b/frontend/src/components/AdminConfigValueEditor.vue
index fe4a758..8ba8429 100644
--- a/frontend/src/components/AdminConfigValueEditor.vue
+++ b/frontend/src/components/AdminConfigValueEditor.vue
@@ -128,6 +128,11 @@ const canAddTableField = computed(() => {
     return false
   return !tableStructure.value?.mutableKeys || /^[a-z0-9_-]+$/.test(key)
 })
+const canExtendTable = computed(
+  () =>
+    !vectorType.value &&
+    (!tableStructure.value || tableStructure.value.mutableKeys === true),
+)
 const tableEntries = computed(() =>
   Object.entries(tableValue.value).filter(
     ([key]) => key !== '__skyType' && (!mapType.value || key !== 'entries'),
@@ -821,7 +826,7 @@ function mapEntryStructure(
     </form>
 
     <form
-      v-else-if="!vectorType"
+      v-else-if="canExtendTable"
       class="config-structured-editor__add-field"
       @submit.prevent="addTableField"
     >
diff --git a/frontend/src/components/AdminPanel.contract.test.ts b/frontend/src/components/AdminPanel.contract.test.ts
index 805290a..68a1278 100644
--- a/frontend/src/components/AdminPanel.contract.test.ts
+++ b/frontend/src/components/AdminPanel.contract.test.ts
@@ -277,6 +277,13 @@ describe('standalone admin panel contracts', () => {
     expect(source).toContain('<AdminConfigValueEditor')
     expect(configuratorValueEditor).toContain('function addListRow()')
     expect(configuratorValueEditor).toContain('function addTableField()')
+    expect(configuratorValueEditor).toContain(
+      'const canExtendTable = computed(',
+    )
+    expect(configuratorValueEditor).toContain(
+      'tableStructure.value.mutableKeys === true',
+    )
+    expect(configuratorValueEditor).toContain('v-else-if="canExtendTable"')
     expect(configuratorValueEditor).toContain('function removeListRow(')
     expect(configuratorValueEditor).toContain('function removeTableField(')
     expect(configuratorValueEditor).toContain('function addMapEntry()')