implement filter drag and drop sorting

js/PrefFilterTree.js

@@ -1,6 +1,22 @@
 dojo.provide("fox.PrefFilterTree");
 
 dojo.require("lib.CheckBoxTree");
+dojo.require("dojo.data.ItemFileWriteStore");
+
+dojo.declare("fox.PrefFilterStore", dojo.data.ItemFileWriteStore, {
+
+	_saveEverything: function(saveCompleteCallback, saveFailedCallback,
+								newFileContentString) {
+
+		dojo.xhrPost({
+			url: "backend.php",
+			content: {op: "pref-filters", method: "savefilterorder",
+				payload: newFileContentString},
+			error: saveFailedCallback,
+			load: saveCompleteCallback});
+	},
+
+});
 
 dojo.declare("fox.PrefFilterTree", lib.CheckBoxTree, {
 	_createTreeNode: function(args) {
@@ -48,5 +64,17 @@ dojo.declare("fox.PrefFilterTree", lib.CheckBoxTree, {
 		return (!item.error || item.error == '') ? "dijitTreeRow" :
 			"dijitTreeRow Error";
 	},
+	checkItemAcceptance: function(target, source, position) {
+		var item = dijit.getEnclosingWidget(target).item;
+
+		// disable copying items
+		source.copyState = function() { return false; };
+
+		return position != 'over';
+	},
+	onDndDrop: function() {
+		this.inherited(arguments);
+		this.tree.model.store.save();
+	},
 });