Submenu should appear on mouseover

Hi
I am building a site using the life template. I have sub menu items and I don't want them to appear always. Either by click or by mouseover they should appear. When I do choose in the menu module "Show Sub Menus" = "NO", it works almost but the problem is that the whole menu closes after clicking and you have to reopen the menu item to see the sub menus. The menu entry has to stay open, only the sub menu should appear after clicking or after mouseover

Thanks for your help
the domain is www.gemeng-ell.lu