Tkinter: neither underline=1 nor bind() work on a Button

[morden]

Here is modified snippet from Dialog.py:

if __name__ == '__main__':
     t = Button(None, {'text': 'Test',
                       'command': _test,
                       Pack: {}}, underline=1)
     t.bind('<Key-Meta_L>, <Key-t>', _test)
     t.bind('<Key-Alt_L>, <Key-t>', _test)
     t.bind('<Key-t>', _test)
     q = Button(None, {'text': 'Quit',
                       'command': t.quit,
                       Pack: {}})
     t.mainloop()


Alt-t does not work. Neither does Ctrl-t or plain t.
Pressing the button with the mouse does invoke _test.
Alt-e does not work.

Any ideas on how to fix this?