When I rotate a Combobox and click on it to view its drop down, it appears black. Same is true for a rotated List.
This appears to be regression with the Nimbus L&F being set as default. 
This is seen with 6u10 b14 on a WinXP Sp2 with the latest SDK build249.
Testcase and snapshot attached for reference.
When a clip is applied on a ComponentView with a List as component, portion of the List within the clip appears black. Reproducible with build 258. Run the below code to reproduce:

import javafx.gui.*;

Frame {
    content: Canvas {
        content: [Group {
            content: [Circle {
                centerX: 0
                centerY: 0
                radius: 105
                fill: Color.RED
            }]
        }, Group {
            clip: Circle {
                centerX: 0
                centerY: 0
                radius: 105
            }
            content: [ComponentView {
                component: List {
                    items: for (i in [1..9]) { ListItem { text: "ListItem{i}" } }
                }
                translateX: 50
                translateY: 50
            }, ComponentView {
                component: Button {
                    text: "Click Me"
                }
                translateX: 50
                translateY: 15
            }]
        }]
    }
    width: 300
    height: 300
    visible: true
};