3 files changed, 46 insertions, 32 deletions

diff --git a/devtools/client/shared/widgets/TableWidget.js b/devtools/client/shared/widgets/TableWidget.js
index 9b6811731..a0f0dfc11 100644
--- a/devtools/client/shared/widgets/TableWidget.js
+++ b/devtools/client/shared/widgets/TableWidget.js
@@ -143,7 +143,12 @@ TableWidget.prototype = {
    */
   set selectedRow(id) {
     for (let column of this.columns.values()) {
-      column.selectRow(id[this.uniqueId] || id);
+      if (id) {
+        column.selectRow(id[this.uniqueId] || id);
+      } else {
+        column.selectedRow = null;
+        column.selectRow(null);
+      }
     }
   },
 
@@ -842,7 +847,8 @@ TableWidget.prototype = {
       column.remove(item);
       column.updateZebra();
     }
-    if (this.items.size == 0) {
+    if (this.items.size === 0) {
+      this.selectedRow = null;
       this.tbody.setAttribute("empty", "empty");
     }
 
@@ -885,6 +891,8 @@ TableWidget.prototype = {
     this.tbody.setAttribute("empty", "empty");
     this.setPlaceholderText(this.emptyText);
 
+    this.selectedRow = null;
+
     this.emit(EVENTS.TABLE_CLEARED, this);
   },
 
@@ -1227,15 +1235,16 @@ Column.prototype = {
    */
   selectRowAt: function (index) {
     if (this.selectedRow != null) {
-      this.cells[this.items[this.selectedRow]].toggleClass("theme-selected");
+      this.cells[this.items[this.selectedRow]].classList.remove("theme-selected");
     }
-    if (index < 0) {
+
+    let cell = this.cells[index];
+    if (cell) {
+      cell.classList.add("theme-selected");
+      this.selectedRow = cell.id;
+    } else {
       this.selectedRow = null;
-      return;
     }
-    let cell = this.cells[index];
-    cell.toggleClass("theme-selected");
-    this.selectedRow = cell.id;
   },
 
   /**
@@ -1399,7 +1408,6 @@ Column.prototype = {
     this.cells = [];
     this.items = {};
     this._itemsDirty = false;
-    this.selectedRow = null;
     while (this.header.nextSibling) {
       this.header.nextSibling.remove();
     }
@@ -1430,7 +1438,7 @@ Column.prototype = {
     }
 
     if (this.selectedRow) {
-      this.cells[this.items[this.selectedRow]].toggleClass("theme-selected");
+      this.cells[this.items[this.selectedRow]].classList.remove("theme-selected");
     }
     this.items = {};
     // Otherwise, just use the sorted array passed to update the cells value.
@@ -1440,7 +1448,7 @@ Column.prototype = {
       this.cells[i].id = item[this.uniqueId];
     });
     if (this.selectedRow) {
-      this.cells[this.items[this.selectedRow]].toggleClass("theme-selected");
+      this.cells[this.items[this.selectedRow]].classList.add("theme-selected");
     }
     this._itemsDirty = false;
     this.updateZebra();
@@ -1454,7 +1462,9 @@ Column.prototype = {
       if (!cell.hidden) {
         i++;
       }
-      cell.toggleClass("even", !(i % 2));
+
+      let even = !(i % 2);
+      cell.classList.toggle("even", even);
     }
   },
 
@@ -1590,8 +1600,8 @@ Cell.prototype = {
     return this._value;
   },
 
-  toggleClass: function (className, condition) {
-    this.label.classList.toggle(className, condition);
+  get classList() {
+    return this.label.classList;
   },
 
   /**
diff --git a/devtools/client/storage/test/browser_storage_sidebar_update.js b/devtools/client/storage/test/browser_storage_sidebar_update.js
index 419d63020..92547815a 100644
--- a/devtools/client/storage/test/browser_storage_sidebar_update.js
+++ b/devtools/client/storage/test/browser_storage_sidebar_update.js
@@ -26,7 +26,7 @@ add_task(function* () {
   for (let i = 0; i < UPDATE_COUNT; i++) {
     info(`Performing update #${i}`);
     updates.push(gUI.once("sidebar-updated"));
-    gUI.displayObjectSidebar();
+    gUI.updateObjectSidebar();
   }
   yield promise.all(updates);
 
diff --git a/devtools/client/storage/ui.js b/devtools/client/storage/ui.js
index 27ad307b0..ef07a8e88 100644
--- a/devtools/client/storage/ui.js
+++ b/devtools/client/storage/ui.js
@@ -113,8 +113,8 @@ function StorageUI(front, target, panelWin, toolbox) {
     cellContextMenuId: "storage-table-popup"
   });
 
-  this.displayObjectSidebar = this.displayObjectSidebar.bind(this);
-  this.table.on(TableWidget.EVENTS.ROW_SELECTED, this.displayObjectSidebar);
+  this.updateObjectSidebar = this.updateObjectSidebar.bind(this);
+  this.table.on(TableWidget.EVENTS.ROW_SELECTED, this.updateObjectSidebar);
 
   this.handleScrollEnd = this.handleScrollEnd.bind(this);
   this.table.on(TableWidget.EVENTS.SCROLL_END, this.handleScrollEnd);
@@ -217,7 +217,7 @@ StorageUI.prototype = {
   },
 
   destroy: function () {
-    this.table.off(TableWidget.EVENTS.ROW_SELECTED, this.displayObjectSidebar);
+    this.table.off(TableWidget.EVENTS.ROW_SELECTED, this.updateObjectSidebar);
     this.table.off(TableWidget.EVENTS.SCROLL_END, this.handleScrollEnd);
     this.table.off(TableWidget.EVENTS.CELL_EDIT, this.editItem);
     this.table.destroy();
@@ -285,17 +285,16 @@ StorageUI.prototype = {
    * being removed was selected.
    */
   removeItemFromTable: function (name) {
-    if (this.table.isSelected(name)) {
+    if (this.table.isSelected(name) && this.table.items.size > 1) {
       if (this.table.selectedIndex == 0) {
         this.table.selectNextRow();
       } else {
         this.table.selectPreviousRow();
       }
-      this.table.remove(name);
-      this.displayObjectSidebar();
-    } else {
-      this.table.remove(name);
     }
+
+    this.table.remove(name);
+    this.updateObjectSidebar();
   },
 
   /**
@@ -634,20 +633,25 @@ StorageUI.prototype = {
    * Populates the selected entry from the table in the sidebar for a more
    * detailed view.
    */
-  displayObjectSidebar: Task.async(function* () {
+  updateObjectSidebar: Task.async(function* () {
     let item = this.table.selectedRow;
-    if (!item) {
-      // Make sure that sidebar is hidden and return
-      this.sidebar.hidden = true;
-      return;
-    }
+    let value;
 
     // Get the string value (async action) and the update the UI synchronously.
-    let value;
-    if (item.name && item.valueActor) {
+    if (item && item.name && item.valueActor) {
       value = yield item.valueActor.string();
     }
 
+    // Bail if the selectedRow is no longer selected, the item doesn't exist or the state
+    // changed in another way during the above yield.
+    if (this.table.items.size === 0 ||
+        !item ||
+        !this.table.selectedRow ||
+        item.uniqueKey !== this.table.selectedRow.uniqueKey) {
+      this.hideSidebar();
+      return;
+    }
+
     // Start updating the UI. Everything is sync beyond this point.
     this.sidebar.hidden = false;
     this.view.empty();
@@ -945,7 +949,7 @@ StorageUI.prototype = {
         case REASON.UPDATE:
           this.table.update(item);
           if (item == this.table.selectedRow && !this.sidebar.hidden) {
-            this.displayObjectSidebar();
+            this.updateObjectSidebar();
           }
           break;
       }