Is there a way to add preselected contents when showing the tree? I don't want to show items that are already been selected previously.

var dialogOptions = {
            show: true,
            multiPicker: true,
            view: "treepicker",
            section: 'content',
            treeAlias: 'content',
            // selection: vm.dialogPreSelectContents,
            startNodeId: $scope.dialogData.config.startNode,
            submit: function (model) {
                vm.overlay.show = false;
                vm.overlay = null;
                vm.contents = model.selection;

                // Append Toggle to object
                vm.appendToggle();

            },
            close: function (oldModel) {
                vm.overlay.show = false;
                vm.overlay = null;
            }
        };