We know that Tkinter has a built-in sel tag that applies a selection to a given text range. We want to apply this tag to the entire text in the widget.

We can simply define a function to handle this, as follows (2.05.py):

def select_all(event=None):
  content_text.tag_add('sel', '1.0', 'end')
  return "break"

After doing this, add a callback to the Select All menu item:

edit_menu.add_command(label='Select All', underline=7, accelerator='Ctrl+A', command=select_all)

We also need to bind the function to the Ctrl + A keyboard shortcut. We do this by using the following key bindings (2.05.py):

content_text.bind('<Control-A>', select_all)
content_text.bind('<Control-a>', select_all)

The coding of the Select All feature is complete. To try it out, add some text to the text widget and then click on the menu item, Select All, or use Ctrl + A (accelerator shortcut key).