How to show tooltip over custom QQuickPaintedItem?

[kitfox]

I've created a custom component that extends QQuickPaintedItem. Now I'm trying to figure out how to add a tooltip to it for when the user hovers the mouse above it. I've added at ToolTip as a child, but it is not displaying when the program is run. What's the right way to do this?

                PianorollKeyboard {
                    id: keyboardComponent
                    width: 120
                    Layout.fillHeight: true

                    centerY: scrollViewY.center
                    noteHeight: vertZoom.value
                    
                    ToolTip {
                        visible: hovered
                        text: "Foo"
                    }

                    Component.onCompleted: {
                        load()
                    }
                }