Oana Botisan, Desktop QA Reporter
	Description • 6 years ago

[Notes]:
- This issue is reproducing on Ubuntu 16.04 x64, too, but it's not that evident. On Ubuntu 16.04 the doorhangers just jump for a moment on the screen, but returns its proper place.  

[Affected versions]:
- Latest Nightly 65.0a1
- Beta 64.0b7
- Firefox 63.0.1

[Affected platforms]:
- Ubuntu 18.04 x64

[Steps to reproduce]:
1. Try to trigger two different types of doorhangers in two separate tabs ( permission for google maps to find your location and boredpanda.com doorhanger).
2. Without dismissing the doorhangers switch between the two tabs.
3. Observe the behaviour.

[Expected result]:
- The doorhangers remain in the same place.

[Actual result]:
- The doorhangers move either at the bottom of the screen or at the top of the screen. 

[Regression range]:
- This is a regression, but I can't seem to find the exact pushlog.
- last good build: 2016-12-15
- first bad build: 2016-12-18 
- I will try to find more info as soon as possible. 

[Additional notes]:
- You can see the issue better if the browser is not maximized on the screen.
- The issue disappears only if you refresh the page or restart Firefox, but as soon as you do step 2, the bug is reproducing.
- If they are the same type of doorhanger (e.g the doorhanger from boredpanda.com) the issue is not reproducing.

	:Felipe Gomes (needinfo for replies!)
	Comment 1 • 6 years ago

Could you provide a screen recording to demonstrate the problem?

	Oana Botisan, Desktop QA Reporter
	Comment 2 • 6 years ago

You can see the issue reproducing in the attached gif.

	Matthew N. [:MattN]
	Comment 3 • 6 years ago

This seems to be a <panel> anchoring problem.

	Neil Deakin
	Comment 4 • 6 years ago

Looks to be some Ubuntu or GTK specific issue. I verified that we're calling gtk_window_move() with the correct coordinates as one switches tabs.