Use this command to open a script in a new window. You can open multiple scripts at once. Use the Window menu to switch among the multiple open documents. See Window 1, 2, ... command.
When you open a Test Script Runner Script (extension .tsr) two windows will open. The active window shows the script in a tree view. The other window shows the trace as the script is executed. Use the Windows menu to see both windows as the same time.