My first idea was the same as in Izhaki's answer, but later I think of this, that seems to fullfil your goal and reduces (at least a bit) the need of user interaction without drawbacks. <!-- Begin mockup: In order to preserve an editable mockup, please don't edit this section directly. Click the "edit" link below the image in the preview instead. --> ![mockup](https://i.sstatic.net/ReyIH.png) <!-- End mockup -->