### Preflight Checklist

- [X] I have read the [Contributing Guidelines](https://github.com/electron/electron/blob/master/CONTRIBUTING.md) for this project.
- [X] I agree to follow the [Code of Conduct](https://github.com/electron/electron/blob/master/CODE_OF_CONDUCT.md) that this project adheres to.
- [X] I have searched the [issue tracker](https://www.github.com/electron/electron/issues) for a feature request that matches the one I want to file, without success.

### Electron Version

12.0.5

### What operating system are you using?

Ubuntu

### Operating System Version

Ubuntu 21.04 x86_64 5.11.0-16-generic

### What arch are you using?

x64

### Last Known Working Electron version

_No response_

### Expected Behavior

All clicking inside the developer tool works well and not being interrupted by dragging the electron app.

### Actual Behavior

When I click the `option` and `close` tool inside the developer tool, it drags the electron app.

https://user-images.githubusercontent.com/61906684/118137437-666fd600-b42f-11eb-9443-ea1ebad1d0ec.mp4



### Testcase Gist URL

_No response_

### Additional Information

This bug only occurs if the dock position is on the left.
shell/browser/ui/views/inspectable_web_contents_view_views.cc
InspectableWebContents* inspectable_web_contents) {
  return new InspectableWebContentsViewViews(inspectable_web_contents);
}
InspectableWebContentsViewViews::InspectableWebContentsViewViews(
    InspectableWebContents* inspectable_web_contents)
    : inspectable_web_contents_(inspectable_web_contents),
      devtools_web_view_(new views::WebView(nullptr)),
      title_(u"Developer Tools") {
  if (!inspectable_web_contents_->IsGuest() &&
      inspectable_web_contents_->GetWebContents()->GetNativeView()) {
    auto* contents_web_view = new views::WebView(nullptr);
    contents_web_view->SetWebContents(
        inspectable_web_contents_->GetWebContents());
    contents_web_view_ = contents_web_view;
  } else {
    contents_web_view_ = new views::Label(u"No content under offscreen mode");
  }
  devtools_web_view_->SetVisible(false);
  AddChildView(devtools_web_view_);
  AddChildView(contents_web_view_);
}
InspectableWebContentsViewViews::~InspectableWebContentsViewViews() {
  if (devtools_window_)
    inspectable_web_contents()->SaveDevToolsBounds(
        devtools_window_->GetWindowBoundsInScreen());
}
views::View* InspectableWebContentsViewViews::GetView() {