heatmap: fix error while loading panel in editor mode

public/app/plugins/panel/heatmap/rendering.ts

@@ -769,8 +769,9 @@ export default function link(scope, elem, attrs, ctrl) {
 
     if (setElementHeight()) {
 
+      if (data) {
         // Draw default axes and return if no data
-      if (!data || _.isEmpty(data.buckets)) {
+        if (_.isEmpty(data.buckets)) {
           addHeatmapCanvas();
           addAxes();
           return;
@@ -789,6 +790,9 @@ export default function link(scope, elem, attrs, ctrl) {
         $heatmap.on("mousedown", onMouseDown);
         $heatmap.on("mousemove", onMouseMove);
         $heatmap.on("mouseleave", onMouseLeave);
+      } else {
+        return;
+      }
     }
 
     // Draw only if color editor is opened