- Electron version: 0.37.5
- Operating system: Mac OS X 10.11.4

When I pass `backgroundColor: '#FF0000' to a window, the color that shows up on the screen is actually '#FF301E'. 

atom/browser/api/atom_api_web_contents.cc
#include "atom/browser/api/atom_api_web_contents.h"
#include <set>
#include <string>
#include "atom/browser/api/atom_api_debugger.h"
#include "atom/browser/api/atom_api_session.h"
#include "atom/browser/api/atom_api_window.h"
#include "atom/browser/atom_browser_client.h"
#include "atom/browser/atom_browser_context.h"
#include "atom/browser/atom_browser_main_parts.h"
#include "atom/browser/atom_security_state_model_client.h"
#include "atom/browser/native_window.h"
#include "atom/browser/net/atom_network_delegate.h"
#include "atom/browser/web_contents_permission_helper.h"
#include "atom/browser/web_contents_preferences.h"
#include "atom/browser/web_view_guest_delegate.h"
#include "atom/common/api/api_messages.h"
#include "atom/common/api/event_emitter_caller.h"
#include "atom/common/mouse_util.h"