lib/Ext/viewport/WindowsPhone.js
function(e) {
            var srcElement = e.srcElement.nodeName.toUpperCase(),
                selectableElements = ['INPUT', 'TEXTAREA'];

            if (selectableElements.indexOf(srcElement) == -1) {
                return false;
            }
        }
function(e) {
            var srcElement = e.srcElement.nodeName.toUpperCase(),
                selectableElements = ['INPUT', 'TEXTAREA'];

            if (selectableElements.indexOf(srcElement) == -1) {
                return false;
            }
        }
There is -ms-user-select CSS property for IE10, but it seems it works only in desktop browser. So we need to prevent selection event.