Close sub-menus when different item at the same level is selected (wh…

…ich doesn't have children)

Fixes #12363

Auditors: @petemill

Test Plan:
1. Launch Brave and open the Hamburger / Kabob / Food menu
2. Move mouse to "New Session Tab" and observe menu come up
3. Move mouse down to next item, "New Window"
4. Submenu for "New Session Tab" should now disappear

app/renderer/components/common/contextMenu/contextMenuItem.js

@@ -123,19 +123,42 @@ class ContextMenuItem extends ImmutableComponent {
 
   onMouseEnter (e) {
     if (this.props.contextMenuItem.has('folderKey')) {
+      // Context menu item in bookmarks toolbar (bookmarks always have a folder id)
       const yAxis = this.getYAxis(e)
       windowActions.onShowBookmarkFolderMenu(this.props.contextMenuItem.get('folderKey'), yAxis, null, this.props.submenuIndex)
     } else if (this.hasSubmenu) {
+      // Regular context menu with submenu (ex: hamburger menu)
       let openedSubmenuDetails = this.props.contextMenuDetail.get('openedSubmenuDetails')
+
       openedSubmenuDetails = openedSubmenuDetails
         ? openedSubmenuDetails.splice(this.props.submenuIndex, openedSubmenuDetails.size)
         : new Immutable.List()
       const yAxis = this.getYAxis(e)
+
       openedSubmenuDetails = openedSubmenuDetails.push(Immutable.fromJS({
         y: yAxis,
-        template: this.submenu
+        template: this.submenu,
+        openerSubmenuIndex: this.props.submenuIndex,
+        openerDataIndex: this.props.dataIndex
       }))
+
       windowActions.setContextMenuDetail(this.props.contextMenuDetail.set('openedSubmenuDetails', openedSubmenuDetails))
+    } else {
+      // Regular context menu item (no children)
+      let openedSubmenuDetails = this.props.contextMenuDetail && this.props.contextMenuDetail.get('openedSubmenuDetails')
+
+      // If a menu is open, see if the submenuIndex matches
+      if (openedSubmenuDetails) {
+        for (let i = 0; i < openedSubmenuDetails.size; i++) {
+          if (this.props.submenuIndex === openedSubmenuDetails.getIn([i, 'openerSubmenuIndex'])) {
+            // When index matches, menu should be closed
+            // User is hovering over a different item at the same level
+            openedSubmenuDetails = openedSubmenuDetails.remove(i)
+            windowActions.setContextMenuDetail(this.props.contextMenuDetail.set('openedSubmenuDetails', openedSubmenuDetails))
+            break
+          }
+        }
+      }
     }
   }
   getLabelForItem (item) {