Consider a JavaFX application with ComboBox as one of its control. If the program window is placed close to the bottom of the monitor screen, not giving enough space for the drop-down, the drop-down used to show on the top of the ComboBox. But in version 8u40, the drop-down list goes out from the monitor screen, making it is impossible to view/click the items out of the screen.

Related discussion : http://stackoverflow.com/questions/29127272/javafx-combobox-dropdown-go-out-from-the-edges-of-the-screen