* Output of `node_modules/.bin/electron --version`: v3.0.6
* Operating System (Platform and Version): Windows 10 (October Update)

**Expected Behavior**
When using the accelerator "Shift+Backspace" in a `Menu`, the accelerator should be displayed as "Shift+Backspace"

**Actual behavior**
"Shift+Shift+Backspace" is displayed as accelerator in the menu.

**To Reproduce**
See: https://github.com/torjusb/electron-accelerator-bug

**Screenshots**
<img width="385" alt="accelerator" src="https://user-images.githubusercontent.com/53583/47494149-49635f80-d851-11e8-8178-eed38f22e0e2.png">

**Additional info**
This only appears to affect "Shift+Backspace" from limited testing. Accelerators such as "Alt+Backspace", "Shift+M" etc. appears to work fine.
atom/browser/api/atom_api_menu.cc
v8::Local<v8::Value> unused,
                v8::Local<v8::Context> context,
                void* priv) {
  v8::Isolate* isolate = context->GetIsolate();
  Menu::SetConstructor(isolate, base::Bind(&Menu::New));
  mate::Dictionary dict(isolate, exports);
  dict.Set("Menu", Menu::GetConstructor(isolate)->GetFunction());
#if defined(OS_MACOSX)
  dict.SetMethod("setApplicationMenu", &Menu::SetApplicationMenu);
  dict.SetMethod("sendActionToFirstResponder",
                 &Menu::SendActionToFirstResponder);
#endif
}
}  
NODE_BUILTIN_MODULE_CONTEXT_AWARE(atom_browser_menu, Initialize)