Notification popup showing up above other windows

[fhd]

Environment

Ubuntu 14.04
Firefox 40.0.3
Adblock Plus for Firefox 2.6.10.3972

How to reproduce

1. Move the focus to an arbitrary application, ensuring to cover the area around the ABP logo, where notifications show up.
2. Trigger a notification.

Observed behaviour

The notification shows up on top of the active window (see attached screenshot​).

Expected behaviour

The notification should not show up on top of the active window - it should only be on top of the browser window. If that behaviour cannot be achieved, the notification should not show up at all while the browser window is inactive - it can be shown the next time the window is activated.

Sidenotes

Making a screenshot using "Prt Scr" key closes the notification when Firefox is focused which leads to a screenshot without the notification. Having the focus on some other window doesn't close the notification, however, and therefore allows to take screenshots of the notification.

Also, clicking on a non-focused window only closes the notification but doesn't focus that window. Clicks on a focused window are being intercepted and cause the notification to close while other kinds of interaction with a focused window is possible without causing the notification to close (e.g. typing in a terminal window).

[fhd]

Cannot reproduce this on Mac OS X 10.10.4. Considering that Thomas reported this to me, it might be a Linux issue, needs checking.

[greiner]

Note that this issue is not reproducible with the following environment:

Windows 8.1
Firefox 40.0.2
Adblock Plus for Firefox 2.6.10.3972

Windows switches the focus to Firefox before showing the notification and therefore doesn't have this issue. Therefore it appears to be limited to at least Ubuntu or other Linux distributions.

[greiner]

After playing around with it for a bit, it appears that there's nothing we can do to fix this ourselves - at least not without making more significant changes to the panel itself. The panel's level attribute is supposed to determine its relation to other windows and although ​MDN says

On Linux, the default value is top, otherwise, the default value is parent.

even explicitly setting the value to parent doesn't fix the issue. However, someone would need to investigate further what causes this issue so that we can report it to the respective software team.

[trev]

Mass-closing all bugs in Adblock Plus for Firefox module, the codebase of Adblock Plus 3.0 belongs into Platform and User-Interface modules. Old bugs are unlikely to still apply.