diff --git a/packages/runtime-dom/src/modules/props.ts b/packages/runtime-dom/src/modules/props.ts
index dc3ad2fac..8dd9c4376 100644
--- a/packages/runtime-dom/src/modules/props.ts
+++ b/packages/runtime-dom/src/modules/props.ts
@@ -2,6 +2,9 @@ export function patchDOMProp(
   el: any,
   key: string,
   value: any,
+  // the next 3 args are passed only due to potential innerHTML/textContent
+  // overriding existing VNodes, in which case the old tree must be properly
+  // unmounted.
   prevChildren: any,
   parentComponent: any,
   unmountChildren: any