Spumux problem

[Bigfoot73]

I have some major problems to get menus created with spumux look good.

My "highlight image" looks like this:

There are three colors + transparency. (Yellow ellipsis + two other colors to make the edges look smoother.) Spumux does not complain about it.

When I play the dvd the menu looks like this:


Instead of yellow the highlight button is light blue except for some areas (where it seems like some sort of ellipse crossing.

The xml file looks like this:
<subpictures>
<stream>
<spu

force="yes"
start="00:00:00.00"
highlight="./menu/highlight.png"
>
<button name="b1" x0="180" y0="020" x1="580" y1="148" up="bn" down="b2" left="bn" right="b2" />
<button name="b2" x0="180" y0="152" x1="580" y1="288" up="b1" down="b3" left="b1" right="b3" />
<button name="b3" x0="180" y0="292" x1="580" y1="418" up="b2" down="b4" left="b2" right="b4" />
<button name="b4" x0="180" y0="422" x1="580" y1="548" up="b3" down="bn" left="b3" right="bn" />
<button name="bn" x0="582" y0="450" x1="680" y1="550" up="b4" down="b1" left="b4" right="b1" />
</spu>
</stream>
</subpictures>
(Just playing with the "highlight" right now. I have tried if it gets better if I specify "image" and "select" as well, but it doesn't.)

So...why does it looks like this??

I also tried to use a single color (the yellow) + transparancy. It seems to work better:


But if you look closer at it the edges between the blue and the yellow are ugly...some are light blue and some are dark gray. Why?