added comment

src/components/views/rooms/EventTile.js

@@ -102,6 +102,8 @@ export function getHandlerTile(ev) {
 
     // sometimes MKeyVerificationConclusion declines to render.  Jankily decline to render and
     // fall back to showing hidden events, if we're viewing hidden events
+    // XXX: This is extremely a hack. Possibly these components should have an interface for
+    // declining to render?
     if (type === "m.key.verification.cancel" && SettingsStore.getValue("showHiddenEventsInTimeline")) {
         const MKeyVerificationConclusion = sdk.getComponent("messages.MKeyVerificationConclusion");
         if (!MKeyVerificationConclusion.prototype._shouldRender.call(null, ev, ev.request)) {