I'm having this problem with Windows 8 RTM and it's get annoying.
When I push the Windows key, I expect the Metro Start to pop-up on the monitor that my mouse is, but the Start appears on the last monitor that it has appeared before.
Even the Wi-Fi panel follows this rule, which is absurd since the Wi-Fi icon is far away, on the first monitor.
Is this controllable? Can I force the Start to open on the monitor my mouse is?