Update ui.fancytree.css

You can also change it so that the gray stays across the full node body instead of just the title:

	.fancytree-node.fancytree-active
{
	border-color: #dfdfdf; /* darker gray border blue */
	border:1px solid transparent;
	background: #e3e3e3; /* Old browsers */
	background: -moz-linear-gradient(top, #f6f6f6 0%, #e3e3e3 100%); /* FF3.6+ */
	background: -webkit-gradient(linear, left top, left bottom, color-stop(0%,#f6f6f6), color-stop(100%,#e3e3e3)); /* Chrome,Safari4+ */
	background: -webkit-linear-gradient(top, #f6f6f6 0%,#e3e3e3 100%); /* Chrome10+,Safari5.1+ */
	background: -o-linear-gradient(top, #f6f6f6 0%,#e3e3e3 100%); /* Opera 11.10+ */
	background: -ms-linear-gradient(top, #f6f6f6 0%,#e3e3e3 100%); /* IE10+ */
	background: linear-gradient(to bottom, #f6f6f6 0%,#e3e3e3 100%); /* W3C */
	filter: progid:DXImageTransform.Microsoft.gradient( startColorstr='#f6f6f6', endColorstr='#e3e3e3',GradientType=0 ); /* IE6-9 */
	
}