Bug 1023511 tracks getting our Windows HiDPI support to parity with the existing OS X Retina support, but there will soon be additional work going on in bug 1016548 to improve Retina support. Note that we need to figure out our general plan for HiDPI on Windows (bug 1023488) before starting this. It's possible that the Retina work will proceed without that, or we figure out the plan soon enough that we fix Retina + Windows in the bug 1016548 work.