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The file tabs
The file tabs show the drawing files that are open in the current session of AutoCAD. You can open as many file tabs as you want and to open any new blank drawing, you can click on the + icon right next to the last file tab:
Figure 1.7: The file tab options
The padlock icon in a file tab indicates that the file is read-only and you can only view that kind of file and not modify it. Hovering the cursor over any open tab also shows the thumbnail preview of the drawing. To open the drawing of the selected tab, simply click on the thumbnail that shows up on the cursor.