in the OverlapX pos you can enter a number and it will make a distance between the menu and sub-menu (0 is menu-submenu, 1 is one pixel between menu-submenu, -1 overlays submenu-menu)
Same as OverlapY (keep the settings I set in here on thy OverlapY, you'll see what I ment why :D)

another thing is the popup itselfs. if there are a lot of "magic pink" elements (transparency) between the entrys, it is also possibe that it dissappers.