Cursor disappearing in webplayer

Hi, folks! I have a problem with cursor disappearing in webplayer. I need to show custom cursors in my webplayer app, so i'm doing it this way:

I'm checking if cursor located inside webplayer object. If true - i'm hiding system cursor ( Screen.showCursor = false; ) and showing custom cursor via GUI.DrawTexture.

Everything is fine, until i do not open another page tab in my browser. When i'm moving cursor over another tab page in browser unity player still gets event "cursor located inside webplayer object" - and hides it! To my mind this bug appeared in Unity 3.2.

I tried to fix this by getting javascript events, like window.blur, window.focus, document.blur, document.focus, but it doesn't work, if webplayer located inside iframe webpage. And the problem is that iframe is only way to place my app in social networks, like facebook.com or vk.com .

Live demo : http://apps.facebook.com/transportergame/