You would just need to make it cover the entire window (and remove the fill animation if you just want the border).
look at
this thread for an explanation on how the anchoring works.
What you would want to do is anchor the pieces as follows
Left attack anim:
Left anchored to left - offset 0 (or the spacing you want between the left border and anim)
Top anchored to top - offset 0 (or the spacing you want between top of window and anim)
Right anchored to
left - offset
width of Left attack anim animtion + left offset
Bottom anchored to bottom - offset 0 (or the spacing you want between bottom of window and anim)
Right attack anim:
Left anchored to right - offset is the width of the anim + right offset
Top anchored to top - offset 0 (or the spacing you want between top of window and anim)
Right anchored to right - offset 0 (or the spacing you want between right of window and anim)
Bottom anchored to bottom - offset 0 (or the spacing you want between bottom of window and anim)
etc...top and bottom are similar except switched between left/right and top/bottom anchors and offsets.
Hopefully that makes some sense.
-- Lashden