When unchecking an item that has hidden checked siblings, uncheck them.

This fixes the cases where multiple facets have been used to restrict a
data set, and unselecting a restriction leads to an empty result set.

@@ -49,6 +49,19 @@ define(function(require) {
             }, this);
             }, this);
             (function(self) {
             (function(self) {
                 var skipCallback;
                 var skipCallback;
+                self.on('item-change', function(item) {
+                    if (item == null) {
+                        debugger;
+                    }
+                    if (item.get('checked')) {
+                        return;
+                    }
+                    this.get('items').each(function(facetItem) {
+                        if (facetItem.get('hidden')) {
+                            facetItem.set('checked', false);
+                        }
+                    });
+                });
                 self.on('item-change change:queryMax change:queryMin', function() {
                 self.on('item-change change:queryMax change:queryMin', function() {
                     switch (skipCallback) {
                     switch (skipCallback) {
                         case 'change:checkedKeys':
                         case 'change:checkedKeys':
@@ -189,7 +202,7 @@ define(function(require) {
             this.set('comparator', options.comparator, {silent: true});
             this.set('comparator', options.comparator, {silent: true});
             this.trigger('change:comparator');
             this.trigger('change:comparator');
             items.on('item-change', function(model, value, options) {
             items.on('item-change', function(model, value, options) {
-                this.trigger('item-change', null, null, options);
+                this.trigger('item-change', model, null, options);
             }, this);
             }, this);
             items.on('update', function(model, value, options) {
             items.on('update', function(model, value, options) {
                 var items = this.get('items');
                 var items = this.get('items');
@@ -536,7 +549,7 @@ define(function(require) {
             this.on('add', function(model, parent, options) {
             this.on('add', function(model, parent, options) {
                 // added to a collection
                 // added to a collection
                 this.on('change:checked', function() {
                 this.on('change:checked', function() {
-                    parent.trigger('item-change');
+                    parent.trigger('item-change', this);
                 });
                 });
             }, this);
             }, this);
             return Item.__super__.initialize.apply(this, arguments);
             return Item.__super__.initialize.apply(this, arguments);