ngOptions selected all options by default and disappearing options on select

Question

I'm having a strange issue I can't seem to troubleshoot with my view. I'm using a directive that generates a treeview of my website. When I select one site, I have two select boxes which populate with the groups in one site and the lists in the site. When the options populate, they are all selected. I've inspected elements and they all have option="selected" Stranger is that, when I click on a single option, all others disappear and only the selected option remains. I've checked the source in Chrome console and yea only the selected option tag remains.

For exmaple the Site Lists select box has multiple options but when I clicked on Old documents, they others all disappeared. In the Site Groups, all groups are already selected Ctrl:

spApp.controller('sitesCtrl',
    function sitesCtrl($scope, $q, $modal, UserService, GroupService, SiteService){
        //Options for tree controller directive
        $scope.treeOptions = {
            nodeChildren: "children",
            dirSelectable: true,
            injectClasses: {
                ul: "a1",
                li: "a2",
                liSelected: "a7",
                iExpanded: "a3",
                iCollapsed: "a4",
                iLeaf: "a5",
                label: "a6",
                labelSelected: "a8"
            }
        }

        //Returns siteMap for tree controller directive 
        $scope.siteMap = SiteService.getSiteMap();

        //Returns selected sites information: grous, lists, title, url
        $scope.showSelected = function(site){
            var siteData = SiteService.getSiteInfo(site);
            //sets sites title and url in view
            $scope.site = site;
            $scope.siteGroups = siteData.groups;
            $scope.siteLists = siteData.lists;
        }

    }
);

View:

    <div class="siteGroups">
        <label for="siteGroups">Site Groups</label>
        <select 
            multiple
            name="siteGroups" 
            id="siteGroups" 
            class="siteGroups"
            ng-model="siteGroups"
            ng-options="g.name for g in siteGroups">
        </select>
    </div>
        <div class="btm1 animated fadeInUp">
        <label for="siteLists">Site Lists </label>
        <select multiple
            id="siteLists" 
            ng-model="siteLists"
            ng-options="l.title for l in siteLists">
        </select>
    </div>

Service and more of the view

Answer 1

This is happening because the ngOptions in the select lists are bounded to the same array as the ngModel. ngModel needs to be a different array that holds only the selected values.

With siteGroups as an example, what is happening is that the select list options are initialized with siteGroups, and they are all selected because the items are in the ngModel (also the siteGroups array). When you click on one of them, it now removes all other items from ngModel except the one you clicked on. Since ngOptions is bounded to the same list, all the non selected options disappear too.

To fix this, create separate array properties on your scope for the selected values in each list.