Select AllCommand  (Edit Menu)

Use this command to select the entire contents of the code area. To make this command available, place the cursor in the code editor or list view. You could use this command to select all lines of code or items displayed in the list view and then use the Copy command to copy the code or items to the clipboard, Delete command to delete all the code or items, or Paste to replace them with the contents of the Clipboard.

Shortcut: CTRL+A