Panels obstruct maximized windows in dual-monitor setups

Bug #1543642 reported by Michael von Glasow on 2016-02-09
42
This bug affects 8 people
Affects Status Importance Assigned to Milestone
ubuntu-mate
Undecided
Unassigned

Bug Description

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) wrote :

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

Changed in ubuntu-mate:
status: New → Incomplete

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

Changed in ubuntu-mate:
status: Incomplete → New
chris maassen (silentbirdie) wrote :

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

Andre (softtest) wrote :

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) wrote :

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) wrote :

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) wrote :

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

Changed in ubuntu-mate:
status: New → Incomplete
Andre (softtest) wrote :

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.

Changed in ubuntu-mate:
status: Incomplete → New

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.

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