Same thing with the downloadpanel mentioned below.
First mockups in 2010, Safari released in in 2011, and it got added in Firefox sometime in 2013.
Considering the article, wouldn't it be kinda obvious why firefox got hacked? The source code is available.
So are most parts of Chrome, including the sandbox.
Sold to the highest bidder? Most.
Nice to see security-research becoming a racketeering operation.