Don't know what type of menu library you are talking about or even what code you are using. If I lived in your head, I'd ask your brain for all the above.
Good point, my apologies. I'm using the LiquidCrystal Library with the Arduino so the code is rather simple. The menu is a self-designed menu for a project. Basically I display something and I can hit either up or down and the LCD will display something else. For some text I need to display the contrast is set perfectly, but when it displays other text the screen goes dark and I can hardly see what's being displayed.