UserAgent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/63.0.3239.108 Safari/537.36

Steps to reproduce the problem:
1. Turn off laptop screen, use external screen only: xrandr --output HDMI3 --auto --output eDP1 --off
2. Create a new browser window (Ctrl+N)
3. Turn off external screen, use laptop screen only: xrandr --output eDP1 --auto --output HDMI3 --off
4. In window created at 2, go to http://www.w3schools.com/html/html5_draganddrop.asp
5. Use the example "Drag the W3Schools image into the rectangle" to try and drag-n-drop the image to the rectangle to the right.

What is the expected behavior?
The ondragenter, ondragover, ondrop events should be fired.

What went wrong?
The image move, but none of the ondragenter, ondragover, ondrop events are fired, and the image cannot be successfully dropped.

The window created at step 2 remains unable to use drag-n-drop no matter what screen it is on (and even if I return to using the external screen alone). Other browser windows can use drag-n-drop normally.

Did this work before? Yes Not sure

Does this work in other browsers? Yes

Chrome version: 63.0.3239.108  Channel: n/a
OS Version: Arch
Flash Version: 

I'm posting a new issue for  Issue 562664  (WontFix). While it is a very similar problem, it appears to be a new occurrence of it, under slightly different conditions. 

I started noticing it just yesterday. I use a webapp nearly every day that relies on drag-n-drop and easily reveals this issue. However, I had never used this app with a sequence of internal / external *alone* / internal screen configurations: I would typically use either the internal screen or use internal+external together in a dual display setup.

As far as I can tell, the two cases described in comment #7 of 562664 are behaving fine (as they have since v56).

For completeness: yesterday I also started using Chromium with chrome://flags/#enable-site-per-process Enabled but I have no idea why that would be at all related.