Bug in WinExist and WinClose (only in windows 7?)

[Philostastically]

In Windows 7, when you try and use WinExist or WinClose, and possibly others, it hangs. It did this in on two seperate 7 machines and worked fine on a windows XP machine, this maybe coincidence. I discovered at this was WindowsAPI. GetWindowText method, it was hanging on the SendMessage() for certain hWnd.