I have a bunch of buttons on a window that use -picture .bmp images to show if the button is on or off.
The data for the buttons on and off state comes from a file that changes all the time.
 
What's the proper way to refresh the window and hence re-draw all of the button objects on the window?
 
I am not adding any new objects to the window, I just want to re-draw them all to reflect their on/off state.
 
Looking at the gui docs, not sure what is the correct way to do this.
Thanks for any help
Doug