Thanks for filing the issue!

Unable to reproduce the issue on reported chrome version 70.0.3538.110 using Mac Mojave 10.14.0 with the below mentioned steps.
1. Launched Chrome
2. Connected to a dual monitor
3. Installed the extension "externalmonitoriframe.zip" provided in Comment#0
4. Clicked on the extension icon, observed pop-up.
5. We were able to click everywhere on the pop-up and outside too.
Note: Checked this by moving the window to extended monitor.

@Reporter: As we are not very sure about step no.4 "click something outside of the upper left quadrant" Could you please elaborate on the same. Any further inputs from your end may be helpful.

In the attached screenshot, only the area inside the green rectangle is clickable. outside the green rectangle, the mouse pointer does not turn into a hand for any of the links or click them as you'd expect.

One more condition that we found is that this isn't an issue for an older macbook air, but is for a newer macbook pro and is reproduceable with all of them we've tested.

To summarize, these are the conditions:
1. Newer Macbook Pro
2. macOS Mojave (10.14.0 or 10.14.1)
3. Chrome 70.0.3538.110 (and probably more)
4. Extension with an iFrame and background page.
5. Browser window displayed on an external monitor with laptop screen also open (not mirrored).

Deleted: Screen Shot 2018-11-29 at 9.48.03 AM.png 111 KB

	Screen Shot 2018-11-29 at 9.48.03 AM.png 111 KB View Download

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For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot

Tried checking the issue as per comment#3's steps using Mac 10.14.0 on chrome version 70.0.3538.110
Note: As we do not have dual monitor connector for MacBook Pro, checked the issue using MacBook Air. We couldn't reproduce the issue from our end, hence attaching the screencast of the same for reference.

@Reporter: Could you please have a look at the screen cast and let us know if we have missed anything in the process. It would also be helpful if mentioned, if this is specific to MacBook Pro.

Thanks!

We have also tested on an older Macbook Air and we could not reproduce the issue there. We have found that this issue is specific to our newer Macbook Pros. You didn't miss anything else from your screen cast. You should have ran into the issue otherwise.

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We have also found that if we set the external monitor as the primary display, it fixes the issue (by going into System Preferences -> Displays -> Arrangement and dragging the top white bar from the laptop display to the external display). Very strange.

From comment#10, the issue issue seems to be fixed by altering Primary/external monitor in system preference. In that case could you please let us know if this can be closed.

Thanks!

Switching the primary display is a suboptimal workaround, not a solution. There clearly is a newly introduced bug somewhere preventing clicks in the plugin iframe.

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For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot

From comment#8, it is understood that the issue seems to be specific to MacBook Pro, hence checked the same using chrome version 70.0.3538.110 on MacBook Pro 10.13.6 by connecting it to the external monitor. Yet we could not reproduce the issue from our end.
Note: As already mentioned in Comment#5, we do not have external monitor connector for MacBook Pro 10.14.1, so couldn't check the same on it.

Hence adding label "TE-NeedsTriageHelp" and requesting someone from respective team to have a look into it for further inputs.

Thanks! 

I didn't spot this bug when I submitted a duplicate
https://bugs.chromium.org/p/chromium/issues/detail?id=922010

fwiw - I think the issue relates to having one monitor which is a retina display, and one which is non-retina. That would explain why there was a problem with a macbook pro, but not a macbook air.

My main machine is an iMac 27in - so it isn't a Macbook Pro specific issue.

I'd be willing to take a bet that somewhere deep in the code, chromium is calculating the area that accepts input, and failing to deal with the different pixel density properly :)

also: confirming that making the standard-resolution monitor the primary stops the issue on my setup.

apologies for the comment flood. Couple of additional minor points.

1) I actually have three monitors. One retina, two standard. The bug shows on both the standard monitors.

2) The bug is triggered after the retina screen shows the popup.

a) reload extension
b) show popup on standard monitor
<behaves correctly>
c) show popup on retina monitor
<behaves correctly here>
d) popup is still open on standard monitor: move mouse around over it
<behaves correctly>
e) close popup on standard monitor and re-open it
<only top left quarter accepts mouse input>

 Issue 922010  has been merged into this issue.