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### Issue Details

* **Electron Version:**
  * 12.0.0-beta.1 to 12.0.0-beta.6
* **Operating System:**
  * Windows 10 (2004) 
* **Last Known Working Electron version:**
  * 11.x.x (all of them)

### Expected Behavior
Click on Menu Item opens the submenu of this item

### Actual Behavior
Clicking on menu set with Menu.setApplicationMenu(Menu.buildFromTemplate(topLevelItems)); is not possible. Pressing "ALT" Highlights the menu but nothing more happens

### To Reproduce
Build Application with menu
shell/browser/ui/views/menu_bar.cc
if (initial_focus && initial_focus->GetWidget()) {
    aura::Window* window = initial_focus->GetWidget()->GetNativeWindow();
    if (!window || !window->GetRootWindow())
      return false;
  }
  bool result = views::AccessiblePaneView::SetPaneFocus(initial_focus);
  if (result) {
    std::set<ui::KeyboardCode> reg;
    for (auto* child : GetChildrenInZOrder()) {
      auto* button = static_cast<SubmenuButton*>(child);
      bool shifted = false;
      auto keycode =
          electron::KeyboardCodeFromCharCode(button->accelerator(), &shifted);
      
      
      if (keycode != ui::VKEY_UNKNOWN && reg.find(keycode) != reg.end()) {
        reg.insert(keycode);
        focus_manager()->RegisterAccelerator(
            ui::Accelerator(keycode, ui::EF_NONE),
            ui::AcceleratorManager::kNormalPriority, this);
      }
    }
    
    focus_manager()->RegisterAccelerator(
        ui::Accelerator(ui::VKEY_MENU, ui::EF_ALT_DOWN),
        ui::AcceleratorManager::kNormalPriority, this);
  }
  return result;
}
void MenuBar::RemovePaneFocus() {