Customising AdaptiveMenu for the admin tab panel

The AdaptiveMenu was design for a menu filling the screen width. Our
menu is in a skeleton structure. The new file overwrites the spree
version and takes the container width as reference.

vendor/assets/javascripts/jquery.adaptivemenu.js

@@ -0,0 +1,62 @@
+/*
+ * Original from spree/core/vendor/assets/javascripts/jquery.adaptivemenu.js
+ */
+
+/*
+ * Used for the spree admin tab bar (Orders, Products, Reports etc.).
+ * Using parent's width instead of window width.
+ */
+jQuery.fn.AdaptiveMenu = function(options){
+
+	var options = jQuery.extend({
+		text: "More...",
+		accuracy:0,
+		'class':null,
+		'classLinckMore':null
+	},options);
+
+	var menu = this;
+	var li = $(menu).find("li");
+
+	var width = 0;
+	var widthLi = [];
+	$.each( li , function(i, l){
+		width += $(l).width();
+		widthLi.push( width );
+	});
+
+	var buildingMenu = function(){
+		var windowWidth = $(menu.parent()).width()  - options.accuracy;
+		for(var i = 0; i<widthLi.length; i++ ){
+			if ( widthLi[i] > windowWidth )
+				$( li[i] ).hide();
+			else
+				$( li[i] ).show();
+		}
+		$(menu).find('#more').remove();
+		var hideLi = $(li).filter(':not(:visible)');
+		var lastLi = $(li).filter(':visible').last();
+		if ( hideLi.length > 0 ){
+			var more = $("<li>")
+				.css({"display":"inline-block","white-space":"nowrap"})
+				.addClass(options.classLinckMore)
+				.attr({"id":"more"})
+				.html(options.text)
+				.click(function(){$(this).find('li').toggle()});
+
+			var ul =  $("<ul>")
+				.css({"position":"absolute"})
+				.addClass(options.klass)
+				.html(hideLi.clone()).prepend(lastLi.clone().hide());
+
+			more.append(ul);
+
+			lastLi.hide().before(more);
+		}
+	}
+
+	jQuery(window).resize(buildingMenu);
+
+	jQuery(window).ready(buildingMenu);
+
+};