To resolve missing close icon and aligment issues in 4.2 add this css rules in BoxSelect.css :
Code:
.x-boxselect-item-close {
	width		: 11px;
	height		: 11px;
	background-image: url(http://cdn.sencha.io/ext-4.2.0-gpl/resources/ext-theme-classic/images/tab/tab-default-close.gif);
	filter		: progid:DXImageTransform.Microsoft.Alpha(Opacity=60);
	opacity		: 0.6;
	top		: 2px;
	right		: 2px;
}
.x-boxselect-list {
	margin:0px;
}