made a eventbox invisible in a transparent window??

[pandacriss]

hi everyone
im making a transparent window. look pretty cool (python gtk cairo)
i added some buttons and they look very ugly
so add just images instead buttons, look grate again,even the animated and transparent images look ok, but image don't have "clicked" events
then put images into eventbox, work, but a rectangle surround the image, eventbox is not transparent
there is some way to make them transparent?

i lend here an example script and a image. hope some one can help me =3

import sys
import gobject
import pango
sys.path[:0] = ['/usr/local/lib/python2.4/site-packages/gtk-2.0']
import pygtk
pygtk.require('2.0')
import gtk
from gtk import gdk
import cairo
 
if gtk.pygtk_version < (2,9,0):
    print "PyGtk 2.9.0 or later required"
    raise SystemExit
supports_alpha = False
 
def ejemplo(widget,event,data="....."):
    print data
 
def expose(widget, event):
    global supports_alpha
 
    cr = widget.window.cairo_create()
 
    if supports_alpha == True:
        cr.set_source_rgba(0, 0, 0, 0.6) # Transparent
    else:
        cr.set_source_rgb(1.0, 1.0, 1.0) # Opaque white
 
    # Draw the background
    cr.set_operator(cairo.OPERATOR_SOURCE)
    cr.paint()
 
    cr.fill()
    cr.stroke()
    return False
 
def screen_changed(widget, old_screen=None):
 
    global supports_alpha
 
    # To check if the display supports alpha channels, get the colormap
    screen = widget.get_screen()
    colormap = screen.get_rgba_colormap()
    if colormap == None:
        print 'Your screen does not support alpha channels!'
        colormap = screen.get_rgb_colormap()
        supports_alpha = False
    else:
        print 'Your screen supports alpha channels!'
        supports_alpha = True
 
    # Now we have a colormap appropriate for the screen, use it
    widget.set_colormap(colormap)
 
    return False
 
def main(args):
    win = gtk.Window()
 
    win.set_title('Alpha Demo')
    win.connect('delete-event', gtk.main_quit)
    win.set_app_paintable(True)
    win.connect('expose-event', expose)
    win.connect('screen-changed', screen_changed)
    win.set_decorated(True)
    win.add_events(gdk.BUTTON_PRESS_MASK)
    win.set_default_size(920,460) 
    #win.connect('button-press-event', clicked)    
    screen_changed(win)
    hbox = gtk.HBox(False,0)
    ima = gtk.Image()
    ima.set_from_file("folder_orange_open.png")
    bot = gtk.Button()
    bot.connect("clicked",ejemplo,"folder_orange_open.png")
    bot.add(ima)
    hbox.pack_start(bot,False,False,20)
 
    ima2 = gtk.Image()
    ima2.set_from_file("folder_orange_open.png")
    hbox.pack_start(ima2,False,False,20)
 
    ima3 = gtk.Image()
    ima3.set_from_file("folder_orange_open.png")
    e = gtk.EventBox()
    e.add(ima3)
    e.connect("button_press_event",ejemplo,"eventbox")
    hbox.pack_start(e,False,False,20)
 
 
    vbox = gtk.VBox(False,0)
    vbox.pack_start(hbox,False,True,50)    
    win.add(vbox)
    win.show_all()
    gtk.main()
 
    return True
 
if __name__ == '__main__':
    sys.exit(main(sys.argv))