Rectangle used for invalidation was outside of windows rect of static
controls with SS_ETCHEDHORZ/SS_ETCHEDVERT style because they resize
after creation. Improve test by changing the invalidated rect and
add more details in comment about SS_ETCHEDHORZ/SS_ETCHEDVERT styles.
Signed-off-by: Rafał Harabień <rafalh92@outlook.com>
Signed-off-by: Alexandre Julliard <julliard@winehq.org>