This functionality is supported only if you are using the Classic Agent.
My scripts are failing in Internet Explorer 7.x with the following error [BrowserChild] MainWindow not found.
When recording a new frame file using Set Recovery System, by default Silk Test does not explicitly state that the parent of the window is a browser. To resolve this issue, the "parent Browser" line must be added to the frame file. For example:
[-] window BrowserChild Google [ ] tag "Google" [ ] parent Browser