Optimization of template generation. Lazy dropdown evaluation reduces number of watches dramatically.

Author: odedfos

src/angularjs-dropdown-multiselect.js

@@ -22,7 +22,7 @@ directiveModule.directive('ngDropdownMultiselect', ['$filter', '$document', '$co
 
                 var template = '<div class="multiselect-parent btn-group dropdown-multiselect">';
                 template += '<button type="button" class="dropdown-toggle" ng-class="settings.buttonClasses" ng-click="toggleDropdown()">{{getButtonText()}}&nbsp;<span class="caret"></span></button>';
-                template += '<ul class="dropdown-menu dropdown-menu-form" ng-style="{display: open ? \'block\' : \'none\', height : settings.scrollable ? settings.scrollableHeight : \'auto\' }" style="overflow: scroll" >';
+                template += '<ul class="dropdown-menu dropdown-menu-form" ng-if="open" ng-style="{display: open ? \'block\' : \'none\', height : settings.scrollable ? settings.scrollableHeight : \'auto\' }" style="overflow: scroll" >';
                 template += '<li ng-hide="!settings.showCheckAll || settings.selectionLimit > 0"><a data-ng-click="selectAll()"><span class="glyphicon glyphicon-ok"></span>  {{texts.checkAll}}</a>';
                 template += '<li ng-show="settings.showUncheckAll"><a data-ng-click="deselectAll();"><span class="glyphicon glyphicon-remove"></span>   {{texts.uncheckAll}}</a></li>';
                 template += '<li ng-hide="(!settings.showCheckAll || settings.selectionLimit > 0) && !settings.showUncheckAll" class="divider"></li>';