* 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.h
#ifndef ATOM_BROWSER_API_ATOM_API_MENU_H_
#define ATOM_BROWSER_API_ATOM_API_MENU_H_
#include <memory>
#include <string>
#include "atom/browser/api/atom_api_top_level_window.h"
#include "atom/browser/api/trackable_object.h"
#include "atom/browser/ui/atom_menu_model.h"
#include "base/callback.h"
namespace atom {
namespace api {
class Menu : public mate::TrackableObject<Menu>,
             public AtomMenuModel::Delegate,
             public AtomMenuModel::Observer {
 public:
  static mate::WrappableBase* New(mate::Arguments* args);
  static void BuildPrototype(v8::Isolate* isolate,
                             v8::Local<v8::FunctionTemplate> prototype);
#if defined(OS_MACOSX)
  
  static void SetApplicationMenu(Menu* menu);
  
  static void SendActionToFirstResponder(const std::string& action);
#endif
  AtomMenuModel* model() const { return model_.get(); }