diff --git a/src/public/app/widgets/type_widgets/options/code_notes/code_mime_types.ts b/src/public/app/widgets/type_widgets/options/code_notes/code_mime_types.ts
index af55aba65..dad94b99d 100644
--- a/src/public/app/widgets/type_widgets/options/code_notes/code_mime_types.ts
+++ b/src/public/app/widgets/type_widgets/options/code_notes/code_mime_types.ts
@@ -54,7 +54,7 @@ export default class CodeMimeTypesOptions extends OptionsWidget {
     async optionsLoaded(options: OptionMap) {
         this.$mimeTypes.empty();
 
-        const ungroupedMimeTypes = mimeTypesService.getMimeTypes();
+        const ungroupedMimeTypes = Array.from(mimeTypesService.getMimeTypes());
         const plainTextMimeType = ungroupedMimeTypes.shift();
         const groupedMimeTypes = groupMimeTypesAlphabetically(ungroupedMimeTypes);