Uber Menu too high when I center align

I’m using ubermenu in conjunction with ‘X’ theme on my ‘i4u’ site. I can style the menu to look almost exactly as I’d like it to be, but as soon as I choose “Horizontal Item Alignment: center” [from the plugin options panel], the vertical height of the menu doubles. If I leave the horizontal alignment set to ‘left’ the menu is the perfect height, but the menu items aren’t centered. I’m pulling my hair out with this, please could you advise me?

Thanks guys!