The three symbols above represent typical choices for an open window. The X at the far right closes (exits) the file or window. The other two symbols change the way an open file or window is displayed. Use the left-most button (-) to minimize the window, so that it is not displayed, but can be redisplayed from the task bar, or click the center button to affect the size of the window on your screen.
When a text file that has been edited or changed (such as the correction file portfile.adm, which is overwritten with each update) is closed, you will be asked if you want to save the changes. Answering Yes will cause the changed file to overwrite the previous version. This is the typical procedure with UA's correction file. If you prefer to save a previous file version permanently, you must save it under a distinct filename before closing it.