1068390 - Context menus appear on wrong monitor (or don't appear at all) if you've customized layout.css.devPixelsPerPx, with dual monitors

Status: RESOLVED DUPLICATE of bug 959682

(Core :: DOM: UI Events & Focus Handling, defect)

Description

[Daniel Holbert [:dholbert]]

STR:
 0. Have a dual-monitor setup (with the two monitors side by side).
 1. Set about:config pref layout.css.devPixelsPerPx to 1.5 or 2
 2. Drag your window to the right monitor, but keep it near that monitor's left edge.
 3. Try right-clicking on any page. (e.g. about:home), or typing in the awesomebar, or opening any of the titlebar menus. (You may need to hit "alt" to show a menu.)

ACTUAL RESULTS: Menus appear on the left monitor, even though the window is on the right monitor.

The likelihood of whether this happens or not, for a particular menu, seems to depend on:
 a) how close the "correct" location of the menu is to the left monitor. (The closer, the more likely the bug is to happen.)
 b) how large of a layout.css.devPixelsPerPx value that you chose. (It happens for pretty much all menus I open when I use a value of 2.0, but only for menus towards the left side of the screen when I use a value of 1.5.)

Also, the context-menu for about:config (e.g. if you right-click a pref) simply doesn't show up at all, instead of showing up on the wrong screen.


Nightly 35.0a1 (2014-09-16)
Mozilla/5.0 (X11; Linux x86_64; rv:35.0) Gecko/20100101 Firefox/35.0
System: Ubuntu 14.04 (with gnome-shell), with two 24" Dell monitors

Comment 1

[npiace]

I have the same issue, however using a value of 2 in layout.css.devPixelsPerPx causes the correct behavior in the current nightly release.  A value between 1 and 2 results in context menus, tool bar menus, and address bar to display on wrong window.  Context menu in about:config does work correctly for all tested values (1, 1.2, 1.5, 1.7, 2).

Nightly 40.0a1 (2015-04-10)
Mozilla/5.0 (X11; Linux x86_64; rv:40.0) Gecko/20100101 Firefox/40.0 ID:20150410030204 CSet: fec90cbfbaad
System: CentOS 6.6, XFCE, nvidia proprietary drivers, DPI 96x96, two Dell 24" 4k monitors.

Comment 2

[miabraha]

I can confirm this on my three-monitor multiple-DPI setup.  The behavior is similar in Fedora 22 and Windows 8. The context menu appears on the wrong monitor whether or not Firefox is full screen, and on any monitor.  On my left and right low-DPI monitors the context menus always appear on the wrong screen; on the center high-DPI monitor they appear on the wrong screen if they should have appeared on the left half of the main screen. 

(On the low DPI monitor to the left, the menus appear all the way on the right monitor, skipping the center one entirely!)

Comment 3

[evilsign]

confirm again.
dual monitors which laptop monitor have a high resolution and high dpi settings.
while layout.css.devPixelsPerPx set lower than 2.0.
any context menu will appear on laptop's monitor.

firefox 41.0.1.

Comment 4

[Dustin C. Hatch]

This happens in Thunderbird, too.

Comment 5

[Matthias Hensler]

Reproduceable on Firefox 43.0 for any values of devPixelsPerPx between 1 and 2 (excluding 1.0 and 2.0).

Comment 7

[john]

This is still happening in Firefox (Developer) v75.0b5
3 Monitor setup, context menu always appears on left most monitor.