How do I use source atop blend mode?

The Scirra blend mode template doesn't seem to be working correctly on my computer. I am trying to get the source atop blend mode to work but I don't think it's working as intended with the template.

This is what it looks like

[attachment=1:3me5ar0h][/attachment:3me5ar0h]

I happened to notice that when I changed the "Effects" layer opacity to 99 instead of 100 I actually get the effect that I want which is the source atop effect (I think):

[attachment=0:3me5ar0h][/attachment:3me5ar0h]

But I'd rather not change the opacity at all.

Any ideas here?

I don't know much about blend modes.. but something doesn't seem right to me about that, either..

destination over appears to be affected by this, as well..

maybe I'll have to re-post this in the bugs section of the forum... seems like it's not working as intended

edit: I posted this in the bugs section of the forum if anyone else is interested in following this: