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* Electron version: 2.0.0-beta.3
* Operating system: Ubuntu 16.04.04 LTS

### Expected behavior

App menu should be visible

### Actual behavior

App menu is invisible

### How to reproduce

- Run `electron`
- Observe that the app menu is invisible. It is still possible to open submenus.

![screenshot from 2018-03-14 17-01-18](https://user-images.githubusercontent.com/19880051/37415303-7296c25e-27ab-11e8-8284-d213c8bf5230.png)

atom/browser/native_window_views.cc
namespace {
#if defined(OS_WIN)
const int kMenuBarHeight = 20;
#else
const int kMenuBarHeight = 25;
#endif
#if defined(OS_WIN)
void FlipWindowStyle(HWND handle, bool on, DWORD flag) {
  DWORD style = ::GetWindowLong(handle, GWL_STYLE);
  if (on)
    style |= flag;
  else
    style &= ~flag;
  ::SetWindowLong(handle, GWL_STYLE, style);
}
#endif
bool IsAltKey(const content::NativeWebKeyboardEvent& event) {
  return event.windows_key_code == ui::VKEY_MENU;
}
bool IsAltModifier(const content::NativeWebKeyboardEvent& event) {
  typedef content::NativeWebKeyboardEvent::Modifiers Modifiers;
  int modifiers = event.GetModifiers();
  modifiers &= ~Modifiers::kNumLockOn;
  modifiers &= ~Modifiers::kCapsLockOn;
  return (modifiers == Modifiers::kAltKey) ||
         (modifiers == (Modifiers::kAltKey | Modifiers::kIsLeft)) ||
         (modifiers == (Modifiers::kAltKey | Modifiers::kIsRight));
}
#if defined(USE_X11)
int SendClientEvent(XDisplay* display, ::Window window, const char* msg) {