That's an onboard graphics card right? They usually are a bit "zicky" (directly translated from "zickenalarm" :)) For example on my notebook with onboard gfx I cannot use the alpha flag alone for some reason, but I have to add the flag 1 to make flag 2 work (or so), see my bug report.
I'd suggest to update your gfx cards drivers, this may or may not solve the issue.
I'd suggest to update your gfx cards drivers, this may or may not solve the issue.