At present there is only one "main" window for the TD. The tools on the Display Management preferences page are useful for sizing and moving the main window, and controlling where dialog windows open. But there's no way to duplicate the main window, meaning to open it in 2 different windows, within the TD. You'll have to use another tool for that. The Windows "duplicate display" feature comes to mind, but that may be problematic, as you have probably already ascertained, if your monitors have different resolutions.