Panels obstruct maximized windows in dual-monitor setups

[Michael von Glasow]

The dimensions of maximized windows seem to get calculated incorrectly in dual-monitor setups.

Steps to reproduce:
1. Use a computer with two displays (I had this issue on a laptop with an external monitor connected) and arrange them vertically (workspace height = combined height of both displays).
2. Align the panels to the top and bottom of the top display.
3. Launch an application on the top display and maximize it.
4. Now align the panels to the top and bottom of the bottom display.
5. Open an application on the bottom display and maximize it.

I would expect the maximized window to occupy the area between the panels (display height minus 2× panel height). Instead, one of the panels overlaps the maximized window: either the one at the top of the bottom screen, or the one at the bottom of the top screen.

Currently on Ubuntu MATE 15.10 with all patches applied, but the issue has been around since 14.10. I've experienced it on two different laptops with a variety of external displays.

I never tested panels aligned to the left and right screen edges with the displays arranged horizontally, but this may present the same issue. Top/bottom-aligned panels with displays arranged horizontally are fine at least if they are on the bigger display (placing them on the smaller display may need testing).

PS: if this bug should be reported upstream, I will happily do that. (If there's some general guideline regarding whether a particular bug should be filed for Ubuntu MATE, upstream or maybe vanilla Ubuntu, a pointer would be appreciated.)

[Martin Wimpress  (flexiondotorg)]

Can you test this using the Ubuntu MATE 16.04 Beta 1 live session and let us know if this is still an issue.

[Michael von Glasow (michael-vonglasow)]

Tested today with a live CD, the issue is still the same.

[chris maassen (silentbirdie)]

I'm having the same problem on the final release of ubuntu-mate 16.04.

[Andre (softtest)]

Seems I'm hitting the same problem. Laptop below a monitor and the top panel hides the window bar of maximised windows.
If switching to single screen or switching from vertical to horizontal layout of screen the window bar becomes visible.
This is with "Ubuntu 16.04.1 LTS"

[Charlie Fyvie-Gauld (cfgsonic)]

Now I've switched over to the actual Ubuntu Mate distribution I'm hitting almost the same problem on 17.04. Here's the hardware configuration:

 [ m1 ][ m2 ]
       [m0]

m1, m2 are external monitors
m0 is the inbuilt laptop display

The panel configuration is so:

 ===================
 @|
 #|
 %|
  |
 v|

The top bar behaves as expected but the additional side-panel I introduced can obcsure a maximised window. Again, from the outside it appears the width does exclude the screen space taken up by the panel and so ends up drawing under it.

It is not always the case though and sometimes they behave as expected in different configurations across the monitors. After a bit more testing I think I've started zeroing in a bit closer to where the problem lies:

Excluding the top-bar which seems to work for me; when a panel is set to an internal edge of the configuration (the vertical edge between [m1] and [m2] or the horizontal edge between [m0] and [m2], for instance) then the panel calculation is incorrect. If, on the other hand, the panel set to an external edge (any edges that do not meet another monitor) then the calculation is as expected.

[Charlie Fyvie-Gauld (cfgsonic)]

Ok, I can't seem to edit posts.

Scratch that about excluding the top bar; it also obscured maximised windows when it lies on an internal edge of the configuration. (I'm somewhat relieved that it is at least consistent!)

[Martin Wimpress  (flexiondotorg)]

Can you test this using an Ubuntu MATE 17.10 daily live iso and let me know if this is still an issue?

[Andre (softtest)]

Yes, the panel obstructs maximized windows still.

Tested with:
- downloaded artful-desktop-amd64.iso (Ubuntu MATE 17.10)
- made bootable usb stick out of it
- booted laptop
- plugged in external screen (hdmi)
- configured display layout with external screen above laptop display and leaving laptop display primary with panels
- opened home folder from places and maximized the window
- result: top window bar (with the close, minimize, maximize icons) is hidden behind the top panel on the laptop display

If you need more details please point me at the right direction.

[Michael von Glasow (michael-vonglasow)]

Confirmed on my side, too (Aug 23 build). Windows still maximize behind panels which are at the edge of a screen but in the middle of the entire display area, no improvement at all so far.

[Junaid Rasheed (jrasheed178)]

Confirmed on Artful and Xenial. If there is a vertical panel on the right monitor, it will overlap any maximized window on the right monitor.

[FreeSoftwareDave (olympicsoftworks-dave)]

My distribution is: 4.10.0-38-generic #42-Ubuntu SMP Tue Oct 10 13:24:27 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux

All new windows that spawn maximized have their drag-bar hidden under the top panel. I have to use ALT and mouse-drag to pull them down when I want to move/close them.

Also the arrangement of one on top of he other is lost when the machine times-out and goes into lock mode. It defaults back to a horizontal multi-monitor set-up and I have to run the monitor tool once more to correct this.

I run stock Mate with MATE Desktop Environment 1.18.0.

[Stian Skjelstad (mywave)]

Still an issue:

$ lsb_release -a
Distributor ID: Ubuntu
Description: Ubuntu 18.04 LTS
Release: 18.04
Codename: bionic

mate-desktop-environment-core 1.20.0+4
xserver-xorg-video-nvidia-390 390.48-0ubuntu3

(positions of screens is preserved, but maximizing a window on the screen that has panels, makes the window partially hidden under the panels)

[Stian Skjelstad (mywave)]

$ xprop -root | grep _NET_WORKAREA\(
_NET_WORKAREA(CARDINAL) = 0, 0, 7680, 3210, 0, 0, 7680, 3210, 0, 0, 7680, 3210, 0, 0, 7680, 3210

$ xprop -root | grep _NET_DESKTOP_GEOMETRY\(
_NET_DESKTOP_GEOMETRY(CARDINAL) = 7680, 3240

$ xrandr
Screen 0: minimum 8 x 8, current 7680 x 3240, maximum 32767 x 32767
DVI-D-0 disconnected (normal left inverted right x axis y axis)
HDMI-0 connected 1920x1080+0+0 (normal left inverted right x axis y axis) 510mm x 290mm
   1920x1080 60.00*+ 59.94 50.00 60.05 60.00 50.04
   1680x1050 59.95
   1280x1024 60.02
   1280x960 60.00
   1280x720 60.00 59.94 50.00
   1152x864 60.00
   1024x768 60.00
   800x600 60.32
   720x576 50.00
   720x480 59.94
   640x480 59.94 59.93
DP-0 disconnected (normal left inverted right x axis y axis)
DP-1 disconnected (normal left inverted right x axis y axis)
DP-2 connected primary 3840x2160+0+1080 (normal left inverted right x axis y axis) 607mm x 345mm
   3840x2160 60.00*+
   2560x1440 59.95
   1920x1080 60.00 59.94
   1680x1050 59.95
   1600x900 60.00
   1440x900 59.89
   1280x1024 75.02 60.02
   1280x800 59.81
   1280x720 60.00
   1152x864 75.00
   1024x768 75.03 70.07 60.00
   800x600 75.00 72.19 60.32 56.25
   640x480 75.00 72.81 59.94
DP-3 disconnected (normal left inverted right x axis y axis)
DP-4 connected 3840x2160+3840+1080 (normal left inverted right x axis y axis) 607mm x 345mm
   3840x2160 60.00*+
   2560x1440 59.95
   1920x1080 60.00 59.94
   1680x1050 59.95
   1600x900 60.00
   1440x900 59.89
   1280x1024 75.02 60.02
   1280x800 59.81
   1280x720 60.00
   1152x864 75.00
   1024x768 75.03 70.07 60.00
   800x600 75.00 72.19 60.32 56.25
   640x480 75.00 72.81 59.94
DP-5 disconnected (normal left inverted right x axis y axis)

[mowestusa (mowestusa)]

I would like to confirm that I experienced this same bug on 19.10 and now 20.04. Reproduced it today, and added this post to the Ubuntu Mate Community forum today.

https://ubuntu-mate.community/t/bottom-panel-bug-with-dual-screen-displays-20-04/21741/4

As the screen shot shows I also have my laptop display below my external display. The external Acer 22" monitor is considered my "primary" so that is the screen where all of my panels are displayed. I have also tested the "familiar" layout on the exact same hardware without the external monitor and when the windows are maximized they do not extend behind the bottom panel. This only seems to occur when there is an external display, and they are stacked vertically.

[Michael von Glasow (michael-vonglasow)]

Great to hear about the fix! Do we know yet whether existing distributions (at least those which are still supported) will be getting this fix?

[Michael von Glasow (michael-vonglasow)]

So, I just noticed that 22.04 with all fixes applied still has the issue. Should this fix be available in 22.04? Or can you tell me which Ubuntu versions got the fix?

[Michael von Glasow (michael-vonglasow)]

I just tested 23.10 from a live USB image, and the issue is fixed there. Conclusion – a fix is available and made it into Ubuntu sometime from 22.10–23.10, but as of December 2023, it has not been backported to 22.04. At least that means I can expect to have a fix some six months from now, when 24.04 gets rolled out as an LTS update.