ToolBarView not rendered if no Element at position M.CENTER

[sebastianwerler]

The following will lead to an unrendered Toolbar:

footer: M.ToolbarView.design({
        childViews: 'title',

        title:M.LabelView.design({
            value: 'FOOTER',
            anchorLocation:M.LEFT
        }),

        anchorLocation: M.BOTTOM
    })

We must add an empty element in the middle to render it:

footer: M.ToolbarView.design({
        childViews: 'middle title',

        middle: M.LabelView.design({
             value: '',
             anchorLocation: M.CENTER
        })

        title:M.LabelView.design({
            value: 'FOOTER',
            anchorLocation:M.LEFT
        }),

        anchorLocation: M.BOTTOM
    })

It must be possible to render ToolBars without having an element in position M.CENTER.