Gosh my eyes must have been blind all the time 
Thanks for pointing out that big fat button.
But still, the layout seems improvable to me. “Software News”, “Changelog” and “Help” are nouns, fundamentally different from “don’t show me anymore” which is a verb, a very general well-expected action for welcome apps that shouldn’t hide among the grid of buttons with no emphasis.
It would be nice if “Software News”, “Changelog” and “Help” are moved to the grid above or to another tab, add a “close” button, and change the “don’t show me anymore” to a checkbox.