Qt Quick Toolbar: Image toolbar for Image-based components shows no filename and wrong thumbnail

If you have the following code in Button.qml,

import Qt 4.7

Image {
     source: "images/button.png"
}

The file where you instantiate the item looks like this:

 Button {} 
 Image { source: "foo.png" }

If you first hover over Image to active the Qt Quick Toolbar, and then hover over Button, foo.png will be displayed as the filename and the thumbnail will be that of foo.png, not images/button.png as one would expect.