avast! Chrome 'Online Security Plugin' doesn't seem to know where it came from!

Some time ago I installed AIS 8.0.1489 on a Vista 32-bit machine. I opened Chrome and was prompted to install 'avast! Online Security Plugin, which I did.

Today, this banner appeared. Guess what, I chose “close”.
Is this a glitch or does the banner generator really not check before making a fool of itself?

Its a glitch. Happened to me. No biggy. Just click on “do not show again”.