Painting is not happening properly , when Choice scrollbar gets disappeared after selected items of the Choice is deleted .

Step to reproduce:
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1) Run the attached program.
2) Click on the Choice, you can see the all the items of the choice & scrollbar.
3) Press Down arrow to delete the item. you can see selected item getting deleted.
4) Repeat step (3) for 7 items. you can see Scrollbar disappears , if you can see some painting issue then bug is reproduced.

This works fine in Tiger RC b63. This problem can be seen in Mustang b42 onward till b77. Hence this is a regression.