Bug 465756 - Plasma panel items showing up on the wrong screen
Summary: Plasma panel items showing up on the wrong screen
Status: RESOLVED WORKSFORME
Alias: None
Product: plasmashell
Classification: Plasma
Component: generic-multiscreen (show other bugs)
Version: 5.27.0
Platform: Arch Linux Linux
: NOR normal
Target Milestone: 1.0
Assignee: Plasma Bugs List
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2023-02-15 11:05 UTC by madcatx
Modified: 2023-02-21 18:27 UTC (History)
4 users (show)

See Also:
Latest Commit:
Version Fixed In:
Sentry Crash Report:

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Description madcatx 2023-02-15 11:05:50 UTC 
- Arch Linux
- Plasma 5.27
- KF5 5.103
- Wayland

1. Start Plasma with multiple displays already online
2. Disconnect an external display
3. Reconnect that same display to the same port.

This might lead to Plasma panel tooltips, Kickoff menu etc. to appear on the wrong screen. This was happening in previous versions too but I was under the impression that 5.27 improvements were supposed to fix issues like this.

kscreen-doctor -o:
Output: 1 eDP-1 enabled connected priority 2 Panel Modes: 0:1920x1080@60*! 1:1680x1050@60 2:1280x1024@60 3:1440x900@60 4:1280x800@60 5:1280x720@60 6:1024x768@60 7:800x600@60 8:640x480@60 9:1280x1024@60 10:1024x768@60 11:1280x800@60 12:1920x1080@60 13:1600x900@60 14:1368x768@60 15:1280x720@60 Geometry: 3840,946 1920x1080 Scale: 1 Rotation: 1 Overscan: 0 Vrr: incapable RgbRange: unknown
Output: 2 HDMI-A-1 enabled connected priority 1 HDMI Modes: 0:3840x2160@60*! 1:3840x2160@60 2:3840x2160@60 3:3840x2160@30 4:3840x2160@30 5:3840x2160@30 6:2560x1600@60 7:2560x1440@60 8:1920x1200@60 9:1920x1080@60 10:1920x1080@60 11:1920x1080@60 12:1920x1080@50 13:1600x1200@60 14:1680x1050@60 15:1600x900@60 16:1280x1024@60 17:1440x900@60 18:1280x800@60 19:1280x720@60 20:1280x720@60 21:1280x720@60 22:1280x720@50 23:1024x768@60 24:800x600@60 25:720x576@50 26:720x576@50 27:720x480@60 28:720x480@60 29:720x480@60 30:720x480@60 31:640x480@60 32:640x480@60 33:640x480@60 34:720x400@70 35:1600x1200@60 36:1280x1024@60 37:1024x768@60 38:2560x1600@60 39:1920x1200@60 40:1280x800@60 41:3840x2160@60 42:3200x1800@60 43:2880x1620@60 44:2560x1440@60 45:1920x1080@60 46:1600x900@60 47:1368x768@60 48:1280x720@60 Geometry: 0,0 3840x2160 Scale: 1 Rotation: 1 Overscan: 0 Vrr: incapable RgbRange: unknown

kscreen-console:
START: Requesting Config
Received config. Took 23 milliseconds
Screen:
        maxSize: QSize(64000, 64000)
        minSize: QSize(0, 0)
        currentSize: QSize(5760, 2160)

-----------------------------------------------------

Id:  1
Name:  "eDP-1"
Type:  "Panel (Laptop)"
Connected:  true
Enabled:  true
Priority:  2
Rotation:  KScreen::Output::None
Pos:  QPoint(3840,946)
MMSize:  QSize(310, 170)
FollowPreferredMode:  false
Size:  QSize(1920, 1080)
Scale:  1
Clones:  None
Mode:  "0"
Preferred Mode:  "0"
Preferred modes:  ("0")
Modes: 
         "0"    "1920x1080@60"   QSize(1920, 1080)   60.033
         "1"    "1680x1050@60"   QSize(1680, 1050)   60.033
         "10"    "1024x768@60"   QSize(1024, 768)   59.92
         "11"    "1280x800@60"   QSize(1280, 800)   59.81
         "12"    "1920x1080@60"   QSize(1920, 1080)   59.963
         "13"    "1600x900@60"   QSize(1600, 900)   59.946
         "14"    "1368x768@60"   QSize(1368, 768)   59.882
         "15"    "1280x720@60"   QSize(1280, 720)   59.855
         "2"    "1280x1024@60"   QSize(1280, 1024)   60.033
         "3"    "1440x900@60"   QSize(1440, 900)   60.033
         "4"    "1280x800@60"   QSize(1280, 800)   60.033
         "5"    "1280x720@60"   QSize(1280, 720)   60.033
         "6"    "1024x768@60"   QSize(1024, 768)   60.033
         "7"    "800x600@60"   QSize(800, 600)   60.033
         "8"    "640x480@60"   QSize(640, 480)   60.033
         "9"    "1280x1024@60"   QSize(1280, 1024)   59.895
EDID Info: 
        Device ID:  "xrandr-AU Optronics"
        Name:  ""
        Vendor:  "AU Optronics"
        Serial:  ""
        EISA ID:  "B140HAN05.7"
        Hash:  "4bf63a6286b847f299a6aeb3c26122c8"
        Width:  31
        Height:  17
        Gamma:  2.2
        Red:  QQuaternion(scalar:1, vector:(0.644531, 0.328125, 0))
        Green:  QQuaternion(scalar:1, vector:(0.300781, 0.603516, 0))
        Blue:  QQuaternion(scalar:1, vector:(0.154297, 0.0546875, 0))
        White:  QQuaternion(scalar:1, vector:(0.313477, 0.329102, 0))

-----------------------------------------------------

Id:  2
Name:  "HDMI-A-1"
Type:  "HDMI"
Connected:  true
Enabled:  true
Priority:  1
Rotation:  KScreen::Output::None
Pos:  QPoint(0,0)
MMSize:  QSize(600, 340)
FollowPreferredMode:  false
Size:  QSize(3840, 2160)
Scale:  1
Clones:  None
Mode:  "0"
Preferred Mode:  "0"
Preferred modes:  ("0")
Modes: 
         "0"    "3840x2160@60"   QSize(3840, 2160)   59.997
         "1"    "3840x2160@60"   QSize(3840, 2160)   60
         "10"    "1920x1080@60"   QSize(1920, 1080)   60
         "11"    "1920x1080@60"   QSize(1920, 1080)   59.94
         "12"    "1920x1080@50"   QSize(1920, 1080)   50
         "13"    "1600x1200@60"   QSize(1600, 1200)   59.997
         "14"    "1680x1050@60"   QSize(1680, 1050)   59.883
         "15"    "1600x900@60"   QSize(1600, 900)   60
         "16"    "1280x1024@60"   QSize(1280, 1024)   60.02
         "17"    "1440x900@60"   QSize(1440, 900)   59.901
         "18"    "1280x800@60"   QSize(1280, 800)   59.91
         "19"    "1280x720@60"   QSize(1280, 720)   60
         "2"    "3840x2160@60"   QSize(3840, 2160)   59.94
         "20"    "1280x720@60"   QSize(1280, 720)   60
         "21"    "1280x720@60"   QSize(1280, 720)   59.94
         "22"    "1280x720@50"   QSize(1280, 720)   50
         "23"    "1024x768@60"   QSize(1024, 768)   60.004
         "24"    "800x600@60"   QSize(800, 600)   60.317
         "25"    "720x576@50"   QSize(720, 576)   50
         "26"    "720x576@50"   QSize(720, 576)   50
         "27"    "720x480@60"   QSize(720, 480)   60
         "28"    "720x480@60"   QSize(720, 480)   60
         "29"    "720x480@60"   QSize(720, 480)   59.94
         "3"    "3840x2160@30"   QSize(3840, 2160)   30
         "30"    "720x480@60"   QSize(720, 480)   59.94
         "31"    "640x480@60"   QSize(640, 480)   60
         "32"    "640x480@60"   QSize(640, 480)   59.94
         "33"    "640x480@60"   QSize(640, 480)   59.94
         "34"    "720x400@70"   QSize(720, 400)   70.082
         "35"    "1600x1200@60"   QSize(1600, 1200)   59.869
         "36"    "1280x1024@60"   QSize(1280, 1024)   59.895
         "37"    "1024x768@60"   QSize(1024, 768)   59.92
         "38"    "2560x1600@60"   QSize(2560, 1600)   59.987
         "39"    "1920x1200@60"   QSize(1920, 1200)   59.885
         "4"    "3840x2160@30"   QSize(3840, 2160)   29.97
         "40"    "1280x800@60"   QSize(1280, 800)   59.81
         "41"    "3840x2160@60"   QSize(3840, 2160)   59.981
         "42"    "3200x1800@60"   QSize(3200, 1800)   59.956
         "43"    "2880x1620@60"   QSize(2880, 1620)   59.96
         "44"    "2560x1440@60"   QSize(2560, 1440)   59.961
         "45"    "1920x1080@60"   QSize(1920, 1080)   59.963
         "46"    "1600x900@60"   QSize(1600, 900)   59.946
         "47"    "1368x768@60"   QSize(1368, 768)   59.882
         "48"    "1280x720@60"   QSize(1280, 720)   59.855
         "5"    "3840x2160@30"   QSize(3840, 2160)   29.981
         "6"    "2560x1600@60"   QSize(2560, 1600)   59.972
         "7"    "2560x1440@60"   QSize(2560, 1440)   59.951
         "8"    "1920x1200@60"   QSize(1920, 1200)   59.95
         "9"    "1920x1080@60"   QSize(1920, 1080)   60
EDID Info: 
        Device ID:  "xrandr-Lenovo Group Limited-LEN P27u-10-1314409779"
        Name:  "LEN P27u-10"
        Vendor:  "Lenovo Group Limited"
        Serial:  "1314409779"
        EISA ID:  ""
        Hash:  "5d384cbea0434a45f0203186a03a6143"
        Width:  60
        Height:  34
        Gamma:  2.2
        Red:  QQuaternion(scalar:1, vector:(0.671875, 0.316406, 0))
        Green:  QQuaternion(scalar:1, vector:(0.207031, 0.712891, 0))
        Blue:  QQuaternion(scalar:1, vector:(0.148438, 0.0556641, 0))
        White:  QQuaternion(scalar:1, vector:(0.313477, 0.329102, 0))

The config file
[ActionPlugins][0]
RightButton;NoModifier=org.kde.contextmenu
wheel:Vertical;NoModifier=org.kde.switchdesktop

[ActionPlugins][1]
RightButton;NoModifier=org.kde.contextmenu

[Containments][104]
activityId=
formfactor=2
immutability=1
lastScreen=0
location=4
plugin=org.kde.panel
wallpaperplugin=org.kde.image

[Containments][104][Applets][105]
immutability=1
plugin=org.kde.plasma.kickoff

[Containments][104][Applets][105][Configuration]
PreloadWeight=100
popupHeight=514
popupWidth=651

[Containments][104][Applets][105][Configuration][ConfigDialog]
DialogHeight=540
DialogWidth=720

[Containments][104][Applets][105][Configuration][General]
favoritesPortedToKAstats=true
icon=/home/madcat/Misc/arch-start-dark.svg
systemFavorites=suspend\\,hibernate\\,reboot\\,shutdown

[Containments][104][Applets][105][Configuration][Shortcuts]
global=Alt+F1

[Containments][104][Applets][106]
immutability=1
plugin=org.kde.plasma.pager

[Containments][104][Applets][106][Configuration]
PreloadWeight=42

[Containments][104][Applets][106][Configuration][ConfigDialog]
DialogHeight=540
DialogWidth=720

[Containments][104][Applets][108]
immutability=1
plugin=org.kde.plasma.marginsseparator

[Containments][104][Applets][108][Configuration]
PreloadWeight=42

[Containments][104][Applets][109]
immutability=1
plugin=org.kde.plasma.systemtray

[Containments][104][Applets][109][Configuration]
PreloadWeight=100
SystrayContainmentId=110

[Containments][104][Applets][121]
immutability=1
plugin=org.kde.plasma.digitalclock

[Containments][104][Applets][121][Configuration]
PreloadWeight=100
popupHeight=450
popupWidth=810

[Containments][104][Applets][121][Configuration][Appearance]
dateFormat=isoDate
selectedTimeZones=America/Los_Angeles,America/New_York,Europe/London,Local
showSeconds=true

[Containments][104][Applets][121][Configuration][ConfigDialog]
DialogHeight=860
DialogWidth=720

[Containments][104][Applets][127]
immutability=1
plugin=org.kde.plasma.taskmanager

[Containments][104][Applets][127][Configuration]
PreloadWeight=42

[Containments][104][Applets][127][Configuration][ConfigDialog]
DialogHeight=540
DialogWidth=720

[Containments][104][Applets][127][Configuration][General]
highlightWindows=false
launchers=preferred://browser,applications:firefox-developer-edition.desktop,applications:org.kde.dolphin.desktop
showOnlyCurrentDesktop=false

[Containments][104][ConfigDialog]
DialogHeight=84
DialogWidth=1920

[Containments][104][Configuration]
PreloadWeight=34

[Containments][104][General]
AppletOrder=105;106;127;108;109;121

[Containments][110]
activityId=
formfactor=2
immutability=1
lastScreen=0
location=4
plugin=org.kde.plasma.private.systemtray
popupHeight=432
popupWidth=432
wallpaperplugin=org.kde.image

[Containments][110][Applets][111]
immutability=1
plugin=org.kde.plasma.clipboard

[Containments][110][Applets][111][Configuration]
PreloadWeight=42

[Containments][110][Applets][112]
immutability=1
plugin=org.kde.plasma.devicenotifier

[Containments][110][Applets][112][Configuration]
PreloadWeight=100

[Containments][110][Applets][113]
immutability=1
plugin=org.kde.plasma.notifications

[Containments][110][Applets][113][Configuration]
PreloadWeight=100

[Containments][110][Applets][114]
immutability=1
plugin=org.kde.plasma.keyboardindicator

[Containments][110][Applets][114][Configuration]
PreloadWeight=42

[Containments][110][Applets][115]
immutability=1
plugin=org.kde.plasma.nightcolorcontrol

[Containments][110][Applets][115][Configuration]
PreloadWeight=42

[Containments][110][Applets][116]
immutability=1
plugin=org.kde.plasma.volume

[Containments][110][Applets][116][Configuration]
PreloadWeight=100

[Containments][110][Applets][116][Configuration][ConfigDialog]
DialogHeight=540
DialogWidth=720

[Containments][110][Applets][116][Configuration][General]
migrated=true

[Containments][110][Applets][117]
immutability=1
plugin=org.kde.plasma.vault

[Containments][110][Applets][117][Configuration]
PreloadWeight=42

[Containments][110][Applets][118]
immutability=1
plugin=org.kde.plasma.printmanager

[Containments][110][Applets][118][Configuration]
PreloadWeight=57

[Containments][110][Applets][119]
immutability=1
plugin=org.kde.plasma.keyboardlayout

[Containments][110][Applets][119][Configuration]
PreloadWeight=42

[Containments][110][Applets][119][Configuration][ConfigDialog]
DialogHeight=540
DialogWidth=720

[Containments][110][Applets][120]
immutability=1
plugin=org.kde.plasma.manage-inputmethod

[Containments][110][Applets][120][Configuration]
PreloadWeight=42

[Containments][110][Applets][123]
immutability=1
plugin=org.kde.plasma.mediacontroller

[Containments][110][Applets][123][Configuration]
PreloadWeight=0

[Containments][110][Applets][124]
immutability=1
plugin=org.kde.plasma.battery

[Containments][110][Applets][124][Configuration]
PreloadWeight=96

[Containments][110][Applets][125]
immutability=1
plugin=org.kde.plasma.networkmanagement

[Containments][110][Applets][125][Configuration]
PreloadWeight=100

[Containments][110][Applets][126]
immutability=1
plugin=org.kde.plasma.bluetooth

[Containments][110][Applets][126][Configuration]
PreloadWeight=0

[Containments][110][Applets][128]
immutability=1
plugin=org.kde.kdeconnect

[Containments][110][Applets][128][Configuration]
PreloadWeight=55

[Containments][110][ConfigDialog]
DialogHeight=540
DialogWidth=720

[Containments][110][Configuration]
PreloadWeight=42

[Containments][110][General]
extraItems=org.kde.plasma.bluetooth,org.kde.plasma.battery,org.kde.plasma.clipboard,org.kde.plasma.devicenotifier,org.kde.plasma.mediacontroller,org.kde.plasma.notifications,org.kde.plasma.keyboardindicator,org.kde.plasma.nightcolorcontrol,org.kde.plasma.networkmanagement,org.kde.plasma.volume,org.kde.plasma.vault,org.kde.plasma.printmanager,org.kde.plasma.keyboardlayout,org.kde.plasma.manage-inputmethod,org.kde.kdeconnect,org.kde.kscreen
hiddenItems=org.kde.kscreen
knownItems=org.kde.plasma.bluetooth,org.kde.plasma.battery,org.kde.plasma.clipboard,org.kde.plasma.devicenotifier,org.kde.plasma.mediacontroller,org.kde.plasma.notifications,org.kde.plasma.keyboardindicator,org.kde.plasma.nightcolorcontrol,org.kde.plasma.networkmanagement,org.kde.plasma.volume,org.kde.plasma.vault,org.kde.plasma.printmanager,org.kde.plasma.keyboardlayout,org.kde.plasma.manage-inputmethod,org.kde.kdeconnect,org.kde.kscreen

[Containments][181][Configuration]
PreloadWeight=42

[Containments][197]
ItemGeometries-1920x1080=
ItemGeometries-3840x2160=
ItemGeometriesHorizontal=
activityId=63f5bb2e-6121-4293-91c0-136b5c645a5f
formfactor=0
immutability=1
lastScreen=0
location=0
plugin=org.kde.desktopcontainment
wallpaperplugin=org.kde.color

[Containments][197][ConfigDialog]
DialogHeight=540
DialogWidth=720

[Containments][197][Wallpaper][org.kde.color][General]
Color=0,0,0

[Containments][198]
ItemGeometries-1920x1080=
ItemGeometries-3840x2160=
ItemGeometriesHorizontal=
activityId=63f5bb2e-6121-4293-91c0-136b5c645a5f
formfactor=0
immutability=1
lastScreen=3
location=0
plugin=org.kde.desktopcontainment
wallpaperplugin=org.kde.color

[Containments][198][ConfigDialog]
DialogHeight=540
DialogWidth=720

[Containments][198][Wallpaper][org.kde.color][General]
Color=0,0,0

[Containments][201]
ItemGeometries-1920x1080=
ItemGeometriesHorizontal=
activityId=63f5bb2e-6121-4293-91c0-136b5c645a5f
formfactor=0
immutability=1
lastScreen=1
location=0
plugin=org.kde.desktopcontainment
wallpaperplugin=org.kde.color

[Containments][201][ConfigDialog]
DialogHeight=540
DialogWidth=720

[Containments][201][Wallpaper][org.kde.color][General]
Color=0,0,0

[Containments][202]
ItemGeometries-1920x1080=
ItemGeometries-3840x2160=
ItemGeometriesHorizontal=
activityId=63f5bb2e-6121-4293-91c0-136b5c645a5f
formfactor=0
immutability=1
lastScreen=4
location=0
plugin=org.kde.plasma.folder
wallpaperplugin=org.kde.image

[Containments][203]
ItemGeometries-1920x1080=
ItemGeometries-3840x2160=
ItemGeometriesHorizontal=
activityId=63f5bb2e-6121-4293-91c0-136b5c645a5f
formfactor=0
immutability=1
lastScreen=2
location=0
plugin=org.kde.desktopcontainment
wallpaperplugin=org.kde.color

[Containments][203][ConfigDialog]
DialogHeight=540
DialogWidth=720

[Containments][203][Wallpaper][org.kde.color][General]
Color=0,0,0

[Containments][205]
ItemGeometries-1920x1080=
ItemGeometries-3840x2160=
ItemGeometriesHorizontal=
activityId=63f5bb2e-6121-4293-91c0-136b5c645a5f
formfactor=0
immutability=1
lastScreen=5
location=0
plugin=org.kde.desktopcontainment
wallpaperplugin=org.kde.color

[Containments][205][ConfigDialog]
DialogHeight=540
DialogWidth=720

[Containments][205][Wallpaper][org.kde.color][General]
Color=0,0,0

[Containments2Appletsts][5][Configuration][General]
highlightWindows=false

[ScreenMapping]
itemsOnDisabledScreens=6,63f5bb2e-6121-4293-91c0-136b5c645a5f,1,desktop:/IDA Freeware 7.6.desktop,1,63f5bb2e-6121-4293-91c0-136b5c645a5f,1,desktop:/Superposition.desktop
screenMapping=desktop:/Old Firefox Data,7,63f5bb2e-6121-4293-91c0-136b5c645a5f
Comment 1 Elias Probst 2023-02-18 10:34:42 UTC 
Potentially related bugs:
- #451449 - Wayland desktop panel doesn't follow primary screen when external primary screen is turned off and back on again (https://bugs.kde.org/show_bug.cgi?id=451449)
- #459082 - Wayland - Notification on primary monitor in wrong place (https://bugs.kde.org/show_bug.cgi?id=459082)

I'm seeing the same here.

I wouldn't say it's not strictly, that items show up on the wrong screen, but that the panel on the primary screen somehow messes up its screen coordinates, as some elements appear on the right screen, but in the wrong place, some are shown on the adjacent screen, some don't show up at all.

My primary screen is (2560x1440, external display) located centered above the secondary screen (1920x1080, laptop built-in). Each screen has a panel at the bottom edge at full width.

Things I can observe here:
- The Kickoff menu (button located at default position, the very left edge of the bottom panel) is shown overlaying the panel at the bottom edge of the screen and moved to the right, as if it would use the secondary screen's geometry to define its X position.
- Panel tooltips use seemingly random positions, either misplaced similarly as the Kickoff menu, or moved downwards to the built-in laptop screen where they appear at the upper edge.
- Right aligned popups from the systray behave similar to what I described for Kickoff (not taking the panel height into account, aligning with the screen's bottom edge instead and not being placed above the systray, being moved to the left as if they'd use the built-in screen's right edge as their maximum for X positioning)
- I have next to the Kickoff button the "Activities" applet, which is supposed to show the Activity Manager on the corresponding screen when clicked. It works just fine, until the screen is re-connected, then clicking on the applet on the primary (external) screen does nothing, clicking on it on the secondary (built-in) screen works just fine. Using the Meta+Q shortcut always triggers it on the secondary (built-in) screen, even when the focus is on the primary (external) screen.

- NixOS unstable
- Plasma 5.27
- KF5 5.103
- Qt 5.15.8
- Kernel 5.15.94

$ kscreen-doctor -o
Output: 1 eDP-1 enabled connected priority 2 Panel Modes: 0:1920x1080@60*! 1:1920x1080@48 2:1280x1024@60 3:1024x768@60 4:1280x800@60 5:1920x1080@60 6:1600x900@60 7:1368x768@60 8:1280x720@60 Geometry: 359,1440 1920x1080 Scale: 1 Rotation: 1 Overscan: 0 Vrr: incapable RgbRange: Automatic
Output: 2 DP-1 enabled connected priority 1 DisplayPort Modes: 0:2560x1440@60*! 1:2048x1080@60 10:1600x1200@60 11:1280x1024@75 12:1280x1024@60 13:1152x864@75 14:1280x720@60 15:1280x720@60 16:1280x720@60 17:1280x720@50 18:1024x768@75 19:1024x768@60 2:2048x1080@24 20:800x600@75 21:800x600@60 22:720x576@50 23:720x576@50 24:720x480@60 25:720x480@60 26:720x480@60 27:720x480@60 28:640x480@75 29:640x480@60 3:1920x1080@60 30:640x480@60 31:640x480@60 32:720x400@70 33:1600x1200@60 34:1280x1024@60 35:1024x768@60 36:1920x1200@60 37:1280x800@60 38:1920x1080@60 39:1600x900@60 4:1920x1080@60 40:1368x768@60 41:1280x720@60 5:1920x1080@60 6:1920x1080@60 7:1920x1080@60 8:1920x1080@50 9:1920x1080@50 Geometry: 0,0 2560x1440 Scale: 1 Rotation: 1 Overscan: 0 Vrr: incapable RgbRange: Automatic

$ kscreen-console
START: Requesting Config
Received config. Took 32 milliseconds
Screen:
maxSize: QSize(64000, 64000)
minSize: QSize(0, 0)
currentSize: QSize(2560, 2520)

-----------------------------------------------------

Id:  1
Name:  "eDP-1"
Type:  "Panel (Laptop)"
Connected:  true
Enabled:  true
Priority:  2
Rotation:  KScreen::Output::None
Pos:  QPoint(359,1440)
MMSize:  QSize(310, 170)
FollowPreferredMode:  false
Size:  QSize(1920, 1080)
Scale:  1
Clones:  None
Mode:  "0"
Preferred Mode:  "0"
Preferred modes:  ("0")
Modes:
"0"    "1920x1080@60"   QSize(1920, 1080)   60.02
"1"    "1920x1080@48"   QSize(1920, 1080)   47.999
"2"    "1280x1024@60"   QSize(1280, 1024)   59.895
"3"    "1024x768@60"   QSize(1024, 768)   59.92
"4"    "1280x800@60"   QSize(1280, 800)   59.81
"5"    "1920x1080@60"   QSize(1920, 1080)   59.963
"6"    "1600x900@60"   QSize(1600, 900)   59.946
"7"    "1368x768@60"   QSize(1368, 768)   59.882
"8"    "1280x720@60"   QSize(1280, 720)   59.855
EDID Info:
Device ID:  "xrandr-unknown"
Name:  ""
Vendor:  ""
Serial:  ""
EISA ID:  "LP140WF6-SPB4"
Hash:  "e831ef9ce9dc2f3aae9e85222a039177"
Width:  31
Height:  17
Gamma:  2.2
Red:  QQuaternion(scalar:1, vector:(0.580078, 0.359375, 0))
Green:  QQuaternion(scalar:1, vector:(0.334961, 0.55957, 0))
Blue:  QQuaternion(scalar:1, vector:(0.160156, 0.120117, 0))
White:  QQuaternion(scalar:1, vector:(0.313477, 0.329102, 0))

-----------------------------------------------------

Id:  2
Name:  "DP-1"
Type:  "DisplayPort"
Connected:  true
Enabled:  true
Priority:  1
Rotation:  KScreen::Output::None
Pos:  QPoint(0,0)
MMSize:  QSize(550, 310)
FollowPreferredMode:  false
Size:  QSize(2560, 1440)
Scale:  1
Clones:  None
Mode:  "0"
Preferred Mode:  "0"
Preferred modes:  ("0")
Modes:
"0"    "2560x1440@60"   QSize(2560, 1440)   59.951
"1"    "2048x1080@60"   QSize(2048, 1080)   59.998
"10"    "1600x1200@60"   QSize(1600, 1200)   60
"11"    "1280x1024@75"   QSize(1280, 1024)   75.025
"12"    "1280x1024@60"   QSize(1280, 1024)   60.02
"13"    "1152x864@75"   QSize(1152, 864)   75
"14"    "1280x720@60"   QSize(1280, 720)   60
"15"    "1280x720@60"   QSize(1280, 720)   60
"16"    "1280x720@60"   QSize(1280, 720)   59.94
"17"    "1280x720@50"   QSize(1280, 720)   50
"18"    "1024x768@75"   QSize(1024, 768)   75.029
"19"    "1024x768@60"   QSize(1024, 768)   60.004
"2"    "2048x1080@24"   QSize(2048, 1080)   23.997
"20"    "800x600@75"   QSize(800, 600)   75
"21"    "800x600@60"   QSize(800, 600)   60.317
"22"    "720x576@50"   QSize(720, 576)   50
"23"    "720x576@50"   QSize(720, 576)   50
"24"    "720x480@60"   QSize(720, 480)   60
"25"    "720x480@60"   QSize(720, 480)   60
"26"    "720x480@60"   QSize(720, 480)   59.94
"27"    "720x480@60"   QSize(720, 480)   59.94
"28"    "640x480@75"   QSize(640, 480)   75
"29"    "640x480@60"   QSize(640, 480)   60
"3"    "1920x1080@60"   QSize(1920, 1080)   60
"30"    "640x480@60"   QSize(640, 480)   59.94
"31"    "640x480@60"   QSize(640, 480)   59.94
"32"    "720x400@70"   QSize(720, 400)   70.082
"33"    "1600x1200@60"   QSize(1600, 1200)   59.869
"34"    "1280x1024@60"   QSize(1280, 1024)   59.895
"35"    "1024x768@60"   QSize(1024, 768)   59.92
"36"    "1920x1200@60"   QSize(1920, 1200)   59.885
"37"    "1280x800@60"   QSize(1280, 800)   59.81
"38"    "1920x1080@60"   QSize(1920, 1080)   59.963
"39"    "1600x900@60"   QSize(1600, 900)   59.946
"4"    "1920x1080@60"   QSize(1920, 1080)   60
"40"    "1368x768@60"   QSize(1368, 768)   59.882
"41"    "1280x720@60"   QSize(1280, 720)   59.855
"5"    "1920x1080@60"   QSize(1920, 1080)   59.94
"6"    "1920x1080@60"   QSize(1920, 1080)   60
"7"    "1920x1080@60"   QSize(1920, 1080)   59.94
"8"    "1920x1080@50"   QSize(1920, 1080)   50
"9"    "1920x1080@50"   QSize(1920, 1080)   50
EDID Info:
Device ID:  "xrandr-DELL U2518D-3C4YP777B5DL"
Name:  "DELL U2518D"
Vendor:  ""
Serial:  "3C4YP777B5DL"
EISA ID:  ""
Hash:  "7d2c5398c171c47f5994bc1778761a77"
Width:  55
Height:  31
Gamma:  2.2
Red:  QQuaternion(scalar:1, vector:(0.639648, 0.328125, 0))
Green:  QQuaternion(scalar:1, vector:(0.299805, 0.599609, 0))
Blue:  QQuaternion(scalar:1, vector:(0.150391, 0.0595703, 0))
White:  QQuaternion(scalar:1, vector:(0.313477, 0.329102, 0))
Comment 2 madcatx 2023-02-18 19:37:39 UTC 
I tried to delete the (rather ancient) Plasma config file and the problem has not reappeared so far. It’s too early to draw any real conclusions but it’s a step worth trying.
Comment 3 Nate Graham 2023-02-21 18:27:30 UTC 
That makes sense.

We completely re-did how multi-monitor data is stores in Plasma 5.27 an added migration code that does its best. But because we know that the multi-monitor situation was a mess in earlier releases, it's not really possible to fully migrate everything 100% perfectly, since it's quite possible that the old config data was already in a broken state. As a result the migration code will never be perfect and issues like this can manifest.

If the issue has not re-appeared after blowing away your old config data, it sounds like the new system is working, so let's count that as a success!