Hi Harikka,
RadWindow is an HTML structure that "lives" in the browser. This means that all browser restrictions related to security and sandboxing apply. Thus, a RadWindow can only move in the viewport of the current browser window and cannot be dragged out of it.
Thus, if your browser spans both monitors, you will be able to move the RadWindow between them.
Regards,
Marin Bratanov
Progress Telerik