I'm sorry if this is redundant but I can't figure it out.  I'm using the online/web wallet (not the local/PC wallet)... how do I claim GAS I've earned?

I go to "Claim"... It's showing "Available Gas" as zero and a balance under "Unavailable Gas" (I only have about 2 GAS at this point btw).

There is a green Claim button I hit (you'd think that would do the trick)... but nothing happens... GAS still unavailable.  And there is nothing else obvious as to how to do this.  Is there a minimum amount you need before you can claim GAS perhaps?

Any help is appreciated!