Comment 2 for bug 10479

Bug 9214 is mainly about cryptic error message. This one focuses the fact the
gksu(do) windows diappears.

I think this windows must not disapears until the granted application is launched
If the pasword is incorrect :
  * try to use the same dialog box to display the error
  * set a WM hint (to inform the user if he is doning something else)
  * propose to enter again the password