IE9 popup windows position in registry

I need to find out registry values that responsible for popup windows position.

I found about follow two settings:

[HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main]
"Window_Placement"=-

[HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Desktop\OldWorkAreas]
"OldWorkAreaRects"=-

But they simply doesn't work.

Problem is that we have some site, that opens popup window (it opens somwhere in center of screen), and this window opens new popup window, that opens with some right and down offset relative to parent window. And its bottom appears out of screen.

One thing does help: reset Internet Explorer settings. After it, second window opens attached to the bottom edge of screen. But not for long. Reset IE each time is very bad solution for us.

So, I need to find out exactlysetting that affected on this.