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### Issue Details

* **Electron Version:**
  * 5.0.3
* **Operating System:**
  * Windows 10 (1809)
* **Last Known Working Electron version:**
  * 4.2.4

### Expected Behavior
Selecting Undo/Redo/Cut/Copy/Paste/ZoomIn/ZoomOut/ResetZoom from menu bar with mouse performs those various functions.

### Actual Behavior
Selecting these options from the menubar using the mouse seems to have no effect.
Using keyboard shortcuts does work ok.

Both mouse & keyboard works ok for all functions in MacOS 10.14.5.

### To Reproduce

https://github.com/electron/fiddle/releases/tag/v0.8.1
Download and run, then try Edit and View menus.
This uses 5.0.1

I have same problem in my own app using 5.0.3. Problem eliminated by downgrading to 4.2.4.

### Additional Information

My app uses standard MenuItem roles:
```
        { role: 'resetzoom' },
        { role: 'zoomin' },
        { role: 'zoomout' },

```

Electron Fiddle does the same:
https://github.com/electron/fiddle/blob/88ce4a76e97c4c93821306b59b3de9a147378058/src/main/menu.ts
```
     item.submenu.push({ type: 'separator' }, { role: 'resetzoom' }, { role: 'zoomin' }, { role: 'zoomout' }); // Add zooming actions
```
shell/browser/ui/views/menu_bar.cc
const ui::NativeTheme* theme = GetNativeTheme();
  if (theme) {
#if defined(USE_X11)
    background_color_ = libgtkui::GetBgColor("GtkMenuBar#menubar");
    enabled_color_ = libgtkui::GetFgColor(
        "GtkMenuBar#menubar GtkMenuItem#menuitem GtkLabel");
    disabled_color_ = libgtkui::GetFgColor(
        "GtkMenuBar#menubar GtkMenuItem#menuitem:disabled GtkLabel");
#else
    background_color_ =
        ui::GetAuraColor(ui::NativeTheme::kColorId_MenuBackgroundColor, theme);
#endif
  }
}
void MenuBar::OnThemeChanged() {
  RefreshColorCache();
  UpdateViewColors();
}
void MenuBar::RebuildChildren() {
  RemoveAllChildViews(true);
  for (int i = 0, n = GetItemCount(); i < n; ++i) {
    auto* button =
        new SubmenuButton(menu_model_->GetLabelAt(i), this, background_color_);
    button->set_tag(i);
    AddChildView(button);
  }
  UpdateViewColors();
}
void MenuBar::UpdateViewColors() {