Created attachment 133811 [details]
destroyed layout, when the main screen is on the right

SUMMARY
Sorry for the old Version of Kmail. At the moment I use Opensuse and I have no time, to install something else.

Kmail doesnt display well on my multi monitor setup. Left the laptop screen, right the external monitor. Native the laptop has 3840x2160, but I use 1920x1080, when the external monitor is plugged in. The external monitor has 3840x2160 and is the main display.


STEPS TO REPRODUCE
1. multi monitor setup, main screen on the right
2. start kmail


OBSERVED RESULT
The layout is destroyed (look at the screen). I guess, the sub windows use the global koordinates, the main window uses the main display koodinates. If I put the 2nd screen virtually to the right and the 1st (=main) screen to the left, then all works fine.

EXPECTED RESULT
Correct Layout, also when the main screen is on the right.

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: 
(available in About System)
KDE Plasma Version: 5.18.5
KDE Frameworks Version: 5.71.0
Qt Version: 5.12.7
kernel: 5.3.18-lp152.50-default
XOrg Version: xorg-x11-server-1.20.3-lp152.8.12.1.x86_64

ADDITIONAL INFORMATION
~ $ /usr/sbin/hwinfo --gfxcard
13: PCI 100.0: 0300 VGA compatible controller (VGA)
[Created at pci.386]
Unique ID: VCu0.Im9kTrXZgn3
Parent ID: vSkL.LMj1nUkYdjC
SysFS ID: /devices/pci0000:00/0000:00:01.0/0000:01:00.0
SysFS BusID: 0000:01:00.0
Hardware Class: graphics card
Model: "nVidia GM204GLM [Quadro M4000M]"
Vendor: pci 0x10de "nVidia Corporation"
Device: pci 0x13f9 "GM204GLM [Quadro M4000M]"
SubVendor: pci 0x17aa "Lenovo"
SubDevice: pci 0x222d
Revision: 0xa1
Driver: "nouveau"
Driver Modules: "nouveau"
Memory Range: 0xc3000000-0xc3ffffff (rw,non-prefetchable)
Memory Range: 0xb0000000-0xbfffffff (ro,non-prefetchable)
Memory Range: 0xc0000000-0xc1ffffff (ro,non-prefetchable)
I/O Ports: 0x4000-0x407f (rw)
Memory Range: 0xc4080000-0xc40fffff (ro,non-prefetchable,disabled)
IRQ: 141 (233059 events)
Module Alias: "pci:v000010DEd000013F9sv000017AAsd0000222Dbc03sc00i00"
Driver Info #0:
Driver Status: nouveau is active
Driver Activation Cmd: "modprobe nouveau"
Config Status: cfg=new, avail=yes, need=no, active=unknown
Attached to: #10 (PCI bridge)

23: PCI 02.0: 0300 VGA compatible controller (VGA)
[Created at pci.386]
Unique ID: _Znp.9rLL5YFZ7w0
SysFS ID: /devices/pci0000:00/0000:00:02.0
SysFS BusID: 0000:00:02.0
Hardware Class: graphics card
Model: "Intel HD Graphics P530"
Vendor: pci 0x8086 "Intel Corporation"
Device: pci 0x191d "HD Graphics P530"
SubVendor: pci 0x17aa "Lenovo"
SubDevice: pci 0x222d
Revision: 0x06
Driver: "i915"
Driver Modules: "i915"
Memory Range: 0xc2000000-0xc2ffffff (rw,non-prefetchable)
Memory Range: 0x60000000-0x6fffffff (ro,non-prefetchable)
I/O Ports: 0x5000-0x503f (rw)
Memory Range: 0x000c0000-0x000dffff (rw,non-prefetchable,disabled)
IRQ: 140 (354930 events)
Module Alias: "pci:v00008086d0000191Dsv000017AAsd0000222Dbc03sc00i00"
Driver Info #0:
Driver Status: i915 is active
Driver Activation Cmd: "modprobe i915"
Config Status: cfg=new, avail=yes, need=no, active=unknown

Primary display adapter: #13

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~ $ loginctl show-session 1 -p Type
Type=x11