One of the features that Ext JS 4 is coming up in the future release is support for touch events. With touch notebooks and desktops being used increasingly, Ext JS 4 is looking at providing responsive behavior to the touch gestures.
Sencha Touch already supports touch events for mobile applications. To bring this feature into Ext JS 4 API, Sencha is looking at creating a sencha-core package that has the common features like the class system, touch events etc, bundled into it.
Though the Ext JS 4 roadmap doesn’t give you much information about the release date, it’s a welcome feature and long pending too. You can read more about it here.