kinda weird - if you open the "main K menu" and run the mouse up and down the window fast (basically faster than it can draw the submenu) then the items show up fine. If you keep the mouse on the menu item long enough (say 2 solid seconds) and then move up one, the item you just left never gets redrawn. sshot attached (ignore the horrible fonts on konsole - i'll do those as a separate bug :)
Created attachment 64610 [details] sshot showing disappearing menus
*** This bug has been marked as a duplicate of 67921 ***