Win Store application, built with Unity 4.5.0 b3 and "Independent Input source" option enabled, doesn't regain focus.

Repro steps:
1. built empty test project with 4.5.0 b3 version and "Independent Input source" option enabled;

2. build and run generated solution;

3. snap to half screen so that you can see the multi-window separator bar that indicates which app has focus. Focus another app or desktop, then click in the test app window to regain focus. Note that the separator bar still indicates that the test app does not have focus.

Reproducible only on 4.5.0 b3;