Maybe a matter of code style, but I would rewrite these to look slightly cleaner, e.g.:
```javascript
dataPanel.on('mousedown touchstart', function (e) {
    var screenX = e.type.indexOf('mouse') === 0 ? e.screenX : e.originalEvent.changedTouches[0].screenX;
    core.dragDataPanelStart(element, screenX, e);
});
dataPanel.on('mouseup mouseout touchend', function (e) { core.dragDataPanelStop(element); });
```