Another angular binding/watcher optimization

src/app/controllers/row.js

@@ -124,4 +124,17 @@ function (angular, app, _) {
     };
   });
 
+  module.directive('panelDropZone', function() {
+    return function(scope, element) {
+      scope.$watch('dashboard.$$panelDragging', function(newVal) {
+        if (newVal && scope.dashboard.rowSpan(scope.row) < 10) {
+          element.show();
+        }
+        else {
+          element.hide();
+        }
+      });
+    };
+  });
+
 });

src/app/panels/graph/module.html

@@ -1,5 +1,4 @@
-<div  ng-controller='GraphCtrl'
-      >
+<div  ng-controller='GraphCtrl'>
 
   <div class="graph-wrapper" ng-class="{'graph-legend-rightside': panel.legend.rightSide}">
       <div class="graph-canvas-wrapper">

src/app/panels/graph/module.js

@@ -243,7 +243,7 @@ function (angular, app, $, _, kbn, moment, timeSeries) {
 
       var data = _.map(results.data, $scope.seriesHandler);
 
-      $scope.datapointsWarning = $scope.datapointsCount || !$scope.datapointsOutside;
+      $scope.datapointsWarning = $scope.datapointsCount === 0 || $scope.datapointsOutside;
 
       $scope.annotationsPromise
         .then(function(annotations) {

src/app/partials/dashboard.html

@@ -110,7 +110,7 @@
                 <grafana-panel type="panel.type" ng-cloak></grafana-panel>
               </div>
 
-              <div ng-show="dashboard.rowSpan(row) < 10 && dashboard.$$panelDragging" class="panel" style="margin:5px;width:30%;background:rgba(100,100,100,0.50)" ng-class="{'dragInProgress':dashboard.panelDragging}" ng-style="{height:row.height}" data-drop="true" ng-model="row.panels" data-jqyoui-options jqyoui-droppable="{index:row.panels.length,mutate:false,onDrop:'panelMoveDrop',onOver:'panelMoveOver',onOut:'panelMoveOut'}">
+              <div panel-drop-zone class="panel dragInProgress" style="margin:5px;width:30%;background:rgba(100,100,100,0.50)" ng-style="{height:row.height}" data-drop="true" ng-model="row.panels" data-jqyoui-options jqyoui-droppable="{index:row.panels.length,mutate:false,onDrop:'panelMoveDrop',onOver:'panelMoveOver',onOut:'panelMoveOut'}">
               </div>
 
               <div class="clearfix"></div>