[Bug][macOS]: browser window dragging capability deactivated on browser view over drag region

[b3ll00z]

Preflight Checklist

• I have read the Contributing Guidelines for this project.
• I agree to follow the Code of Conduct that this project adheres to.
• I have searched the issue tracker for a bug report that matches the one I want to file, without success.

Electron Version

16.0.7

What operating system are you using?

macOS

Operating System Version

macOS Big Sur 11.2.1

What arch are you using?

x64

Last Known Working Electron version

15.0.0

Expected Behavior

Given a frameless browser window with provided html drag region, the browser window itself should be draggable despite any browser view attached

Actual Behavior

Given a frameless browser window with provided html drag region, the dragging capability for the browser window is deactivated by a browser view attached exactly over the drag region

(probably you'll see in the poc that sometimes it's draggable after you resized and dragged the "always"-draggable window).

Testcase Gist URL

https://github.com/b3ll00z/poc-undraggable-frameless

To reproduce

$ git clone https://github.com/b3ll00z/poc-undraggable-frameless
$ cd poc-undraggable-frameless
$ npm install ; npm start

poc_undraggable_window.mov

[codebytere]

This is, unfortunately, behavior by design. I corrected this in #31085. On macOS, draggable regions are implemented making the whole web view draggable and overlaying regions that are not draggable. BrowserViews and BrowserWindows hve independent web views, and so independent exclusion zones. Thus, if a BrowserView with different draggable regions than the BrowserWindow it belongs to is superimposed on top of that window, the draggable regions of the BrowserView take precedence over those of the BrowserWindow.