How to disable pasting text in an entry.

[Anil <anil gdit iiit net>]

Hi !

	I have implemented an entry which functions like a password entry
(MS Windows type) ie when the user types in anything the masking character
'*' appears. But when the user pastes the text through mouse middle click, 
"key_press_event" is not triggered. So the text appears intact. How can i 
disable this? Disable the mouse event entirely or hide the text and show 
the masking character.