Open Dialog Box
       You open this dialog box by clicking . 
You can also open this dialog box from the Project Navigator. Right-click
         the file you want to open in the Files or Design Units tab of the Project Navigator and click
            Open. The Open command in the Project Navigator, however, applies only to files
         included in an open project and the Open dialog box
         does not appear. When you type the file name, you must use the correct slashes for your
         platform. For example, use "\" for Windows.
   
Opens the selected file in the appropriate Intel® Quartus® Prime application, moves the window to the front of the desktop, and makes it available.