Grayed out options ?

Hello, I have recently started using avast and have a question about the sandbox;

Every time my screen-saver tries to launch I get a message from avast saying it may be unsafe, as I know it is legit I would like avast to stop giving me a warning every time.

My problem is the option to tell avast to remember my answer is grayed out.

http://img708.imageshack.us/img708/2469/unled1qp.jpg

Perhaps there is some simple answer which I have missed, but it is starting to bug me now so any help would be much appreciated.

Thanks in advance to anyone willing to help.

If you know it’s safe, you shouldn’t select “Open in sandbox”, but rather “Open normally”.

Its greyed out as you first have to select an option from the drop down list (Open normally), see image example.