Horizontal line in super wingpanel

[Txarli]

I'm using super wingpanel for the intellihide feature. When this is activated, the panel shows a thin grey line (something like a shadow). It isn't something critical, but it's a little bit annoying. You can see it in the picture below.

I'm using Elementary OS Luna. I've tried to find a way to correct this, but I haven't found a solution.

Thank you very much, and nice job!