DevTools: Highlight changed scope variables as they change

Source/devtools/front_end/sources/WatchExpressionsSidebarPane.js

Index: Source/devtools/front_end/sources/WatchExpressionsSidebarPane.js
diff --git a/Source/devtools/front_end/sources/WatchExpressionsSidebarPane.js b/Source/devtools/front_end/sources/WatchExpressionsSidebarPane.js
index 0c9a41124100e4af1076981c007e6de7a3c60e82..0f3ee2c686d642f8e9cb2fd0350384ea16b96932 100644
--- a/Source/devtools/front_end/sources/WatchExpressionsSidebarPane.js
+++ b/Source/devtools/front_end/sources/WatchExpressionsSidebarPane.js
@@ -37,6 +37,11 @@ WebInspector.WatchExpressionsSidebarPane = function()
     WebInspector.SidebarPane.call(this, WebInspector.UIString("Watch Expressions"));
 
     this.section = new WebInspector.WatchExpressionsSection();
+    this.section.pane = this;
+
+    this._expandedExpressions = new Set();
+    this._expandedProperties = new Set();
+
     this.bodyElement.appendChild(this.section.element);
 
     var refreshButton = this.titleElement.createChild("button", "pane-title-button refresh");
@@ -211,6 +216,8 @@ WebInspector.WatchExpressionsSection.prototype = {
             this.element.appendChild(this.emptyElement);
             this.propertiesElement.remove();
             this.propertiesTreeOutline.removeChildren();
+            this.pane._expandedExpressions.clear();
+            this.pane._expandedProperties.clear();
         } else {
             this.element.appendChild(this.propertiesElement);
             this.emptyElement.remove();