#2448 Window not redrawn

[Mats Bengtsson]

If I create a label widget with an image and this image is changed somehow, the widget does not get redrawn until I do something with it, like clicking at it etc. Reproduce this by having two images of the same size and do:

set f1 [tk_getOpenFile]
set f2 [tk_getOpenFile]
set name1 [image create photo -file $f1]
set name2 [image create photo -file $f2]
pack [ttk::label .l -image $name1 -compound image -padding 100]

# wait here and see the result then do

$name1 copy $name2

I'm runng 8.5.2 on an 10.5.2 Mac.
Likely this happened when the extra double buffering was removed.