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 dad94b99d..40e450d19 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
@@ -60,7 +60,9 @@ export default class CodeMimeTypesOptions extends OptionsWidget {
 
         // Plain text is displayed at the top intentionally.
         if (plainTextMimeType) {
-            this.$mimeTypes.append(this.#buildSelectionForMimeType(plainTextMimeType));
+            const $plainEl = this.#buildSelectionForMimeType(plainTextMimeType);
+            $plainEl.find("input").attr("disabled", "");
+            this.$mimeTypes.append($plainEl);
         }
 
         for (const [initial, mimeTypes] of Object.entries(groupedMimeTypes)) {