Update scene while UI opened

I’m getting a bit crazy about Draw callback functions. I make a UIblock with buttons which switch and modify geometry, but I’m not able to update the scene to make changes effected, all just work when the window disappear. Is there a way to make changes visible while user plays whit the buttons?
The program is something like follows:

def modif_geom():
   #THESE are changes I want to be interactively seen

def callb(event,value):
    if e=12:   modif_geom()

def UI()

while GLOBALS['evt']:

you need to close the UIBlock, redraw and open it again. This isnt that nice a solution but it works.

Ok, I was afraid of that, but I’ve found the way. That blinking insn’t so elegant, but it works. As always… Thanks a lot!