need help with skin color - area between explorer background and findexer

I could use some help with a color on a skin.  I recently found Findexer, and really like it.  The skin I found it with and first used it was fine.  Any other skins I see this and can't figure out how to change it.  I attached a screen shot of the current skin I am using.  I changed the background color and also changed the color of Findexer to match, but I have this white line.  I know it is possible to fix, but I just can't seem to find it.  Could anyone lend me some assistance?

Thanks in advance.