* Electron Version: 3.0.0-beta1
* Operating System (Platform and Version): macOS
* Last known working Electron version: 2.0.2

**Expected Behavior**
```css
html, body, * {
    -webkit-app-region: drag;
    -webkit-user-select: none;
    cursor: default;
}
```
should allow users to move the position of the window by dragging it directly.

**Actual behavior**
The window is not draggable.
The `cursor` and `-webkit-user-select` properties work well.

**To Reproduce**
copy the CSS above, paste it into a frameless app's `<style>` tag, and run the app.

**Screenshots**

**Additional Information**

atom/browser/api/atom_api_browser_window.cc
if (!window_unresponsive_closure_.IsCancelled())
    return;
  window_unresponsive_closure_.Reset(
      base::Bind(&BrowserWindow::NotifyWindowUnresponsive, GetWeakPtr()));
  base::ThreadTaskRunnerHandle::Get()->PostDelayedTask(
      FROM_HERE, window_unresponsive_closure_.callback(),
      base::TimeDelta::FromMilliseconds(ms));
}
void BrowserWindow::NotifyWindowUnresponsive() {
  window_unresponsive_closure_.Cancel();
  if (!window_->IsClosed() && window_->IsEnabled() &&
      !IsUnresponsiveEventSuppressed()) {
    Emit("unresponsive");
  }
}
void BrowserWindow::Cleanup() {
  auto* host = web_contents()->GetRenderViewHost();
  if (host)
    host->GetWidget()->RemoveInputEventObserver(this);
  api_web_contents_->DestroyWebContents(true );
  Observe(nullptr);
}
mate::WrappableBase* BrowserWindow::New(mate::Arguments* args) {