- Electron version: 1.2.2
- Operating system: Linux

This is a problem only in linux. It works in OSX.

``` javascript
win.hide()
win.capturePage(function(img){
 // never called
})
```

shell/browser/api/electron_api_web_contents.cc
auto* const host = ontents()->GetMainFrame();
  if (host)
    host->CopyImageAt(x, y);
}
void WebContents::Focus() {
   Focusing on WebContents does not automatically focus the window on macOS
   and Linux, do it manually to match the behavior on Windows.
#if defined(OS_MAC) || defined(OS_LINUX)
  if (owner_window())
    owner_window()->Focus(true);
#endif
  ontents()->Focus();
}
#if !defined(OS_MAC)
bool WebContents::IsFocused() const {
  auto* view = ontents()->GetRenderWidgetHostView();
  if (!view)
    return false;
  if (GetType() != Type::kBackgroundPage) {
    auto* window = ontents()->GetNativeView()->GetToplevelWindow();
    if (window && !window->IsVisible())
      return false;
  }
  return view->HasFocus();
}
#endif
void WebContents::SendInputEvent(v8::Isolate* isolate,