Slide animation with anchors problem

[RodoB]

I don't know how to build a slide animation with an item that is anchored at the sliding direction.
I get a "expand" like animation, not an item sliding from the bottom up and down.
I would thank you for some hints.

Here a code example

Item {
    anchors.fill: parent

    Item {
        id: someItem1
        anchors.top : bottomItem.top // initial state is collapsed
        anchors.right : parent.right
        anchors.left : parent.left
        anchors.bottom : therapyBar.top

        //clipping needed for the animation. The dialog has to slide down without
        //disturbing the objects below.
        clip: true
        states: [
            State {
                name: "collapsed"
                AnchorChanges {
                    target: someItem1
                    anchors.top:bottomItem.top 
                   // what about the bottom anchor here? I would like to keep a fixed height so it slides down.
                }
            },
            State {
                name: "expanded"
                AnchorChanges {
                    target: someItem1
                    anchors.top:parent.top
                }
            }
        ]
    }

    Item {
        id:bottomItem
        anchors.bottom: parent.bottom
        anchors.left: parent.left
        anchors.right: parent.right
        height: 100
        }
}