When disabling a secondary display and re-enabling it again, its position is reset back to being centred with the primary display as soon as the "Enabled" checkbox in the display KCM is clicked.

The position of a secondary display should not be reset when disabling/re-enabling it.

See also: https://plus.google.com/+PeterLemken/posts/hA775eNvkuk
Using:
- Qt 5.10.1
- kwin X11 git/master c0226fe74

kwin supportInformation:
KWin Support Information:
The following information should be used when requesting support on e.g. http://forum.kde.org.
It provides information about the currently running instance, which options are used,
what OpenGL driver and which effects are running.
Please post the information provided underneath this introductory text to a paste bin service
like http://paste.kde.org instead of pasting into support threads.

==========================

Version
=======
KWin version: 5.12.80
Qt Version: 5.10.1
Qt compile version: 5.10.1
XCB compile version: 1.12

Operation Mode: X11 only

Build Options
=============
KWIN_BUILD_DECORATIONS: yes
KWIN_BUILD_TABBOX: yes
KWIN_BUILD_ACTIVITIES: yes
HAVE_DRM: yes
HAVE_GBM: yes
HAVE_X11_XCB: yes
HAVE_EPOXY_GLX: yes
HAVE_WAYLAND_EGL: yes

X11
===
Vendor: The X.Org Foundation
Vendor Release: 11905000
Protocol Version/Revision: 11/0
SHAPE: yes; Version: 0x11
RANDR: yes; Version: 0x14
DAMAGE: yes; Version: 0x11
Composite: yes; Version: 0x4
RENDER: yes; Version: 0xb
XFIXES: yes; Version: 0x50
SYNC: yes; Version: 0x31
GLX: yes; Version: 0x0

Decoration
==========
Plugin: org.kde.breeze
Theme: 
Blur: 0
onAllDesktopsAvailable: true
alphaChannelSupported: true
closeOnDoubleClickOnMenu: false
decorationButtonsLeft: 0, 2, 9
decorationButtonsRight: 6, 3, 4, 5
borderSize: 3
gridUnit: 10
font: Oxygen-Sans,10,-1,5,50,0,0,0,0,0
smallSpacing: 2
largeSpacing: 10

Platform
==========
Name: KWin::X11StandalonePlatform

Options
=======
focusPolicy: 1
nextFocusPrefersMouse: true
clickRaise: true
autoRaise: false
autoRaiseInterval: 0
delayFocusInterval: 0
shadeHover: false
shadeHoverInterval: 250
separateScreenFocus: false
placement: 4
focusPolicyIsReasonable: true
borderSnapZone: 10
windowSnapZone: 10
centerSnapZone: 0
snapOnlyWhenOverlapping: false
rollOverDesktops: true
focusStealingPreventionLevel: 0
legacyFullscreenSupport: false
operationTitlebarDblClick: 5000
operationMaxButtonLeftClick: 5000
operationMaxButtonMiddleClick: 5015
operationMaxButtonRightClick: 5014
commandActiveTitlebar1: 0
commandActiveTitlebar2: 30
commandActiveTitlebar3: 2
commandInactiveTitlebar1: 4
commandInactiveTitlebar2: 30
commandInactiveTitlebar3: 2
commandWindow1: 7
commandWindow2: 8
commandWindow3: 8
commandWindowWheel: 31
commandAll1: 10
commandAll2: 3
commandAll3: 14
keyCmdAllModKey: 16777250
showGeometryTip: true
condensedTitle: false
electricBorderMaximize: true
electricBorderTiling: true
electricBorderCornerRatio: 0.25
borderlessMaximizedWindows: false
killPingTimeout: 5000
hideUtilityWindowsForInactive: true
inactiveTabsSkipTaskbar: false
autogroupSimilarWindows: false
autogroupInForeground: true
compositingMode: 1
useCompositing: true
compositingInitialized: true
hiddenPreviews: 1
glSmoothScale: 2
xrenderSmoothScale: false
maxFpsInterval: 16666666
refreshRate: 0
vBlankTime: 6000000
glStrictBinding: true
glStrictBindingFollowsDriver: true
glCoreProfile: true
glPreferBufferSwap: 101
glPlatformInterface: 1
windowsBlockCompositing: true

Screen Edges
============
desktopSwitching: false
desktopSwitchingMovingClients: false
cursorPushBackDistance: 1x1
timeThreshold: 150
reActivateThreshold: 350
actionTopLeft: 0
actionTop: 0
actionTopRight: 0
actionRight: 0
actionBottomRight: 0
actionBottom: 0
actionBottomLeft: 0
actionLeft: 0

Screens
=======
Multi-Head: no
Active screen follows mouse:  no
Number of Screens: 2

Screen 0:
---------
Name: eDP-1
Geometry: 320,1440,1920x1080
Scale: 1
Refresh Rate: 60.001

Screen 1:
---------
Name: DP-1
Geometry: 0,0,2560x1440
Scale: 1
Refresh Rate: 59.9506


Compositing
===========
Compositing is active
Compositing Type: OpenGL
OpenGL vendor string: Intel Open Source Technology Center
OpenGL renderer string: Mesa DRI Intel(R) Ivybridge Mobile 
OpenGL version string: 4.2 (Core Profile) Mesa 17.3.9
OpenGL platform interface: GLX
OpenGL shading language version string: 4.20
Driver: Intel
GPU class: IvyBridge
OpenGL version: 4.2
GLSL version: 4.20
Mesa version: 17.3.9
X server version: 1.19.5
Linux kernel version: 4.16.1
Direct rendering: Requires strict binding: yes
GLSL shaders:  yes
Texture NPOT support:  yes
Virtual Machine:  no
OpenGL 2 Shaders are used
Painting blocks for vertical retrace:  yes

Loaded Effects:
---------------
mouseclick
kwin4_effect_logout
kwin4_effect_windowaperture
lookingglass
kwin4_effect_frozenapp
kwin4_effect_morphingpopups
kwin4_effect_eyeonscreen
kwin4_effect_login
kwin4_effect_fade
dimscreen
kwin4_effect_dialogparent
kwin4_effect_maximize
slidingpopups
slideback
slide
screenshot
minimizeanimation
glide
flipswitch
desktopgrid
coverswitch
colorpicker
sheet
presentwindows
highlightwindow
blur
windowgeometry
startupfeedback
screenedge
kscreen

Currently Active Effects:
-------------------------
blur

Effect Settings:
----------------
mouseclick:
color1: #ff0000
color2: #00ff00
color3: #0000ff
lineWidth: 1
ringLife: 300
ringSize: 20
ringCount: 2
showText: true
font: Noto Sans,10,-1,5,50,0,0,0,0,0
enabled: false

kwin4_effect_logout:

kwin4_effect_windowaperture:

lookingglass:
initialRadius: 200

kwin4_effect_frozenapp:

kwin4_effect_morphingpopups:

kwin4_effect_eyeonscreen:

kwin4_effect_login:

kwin4_effect_fade:

dimscreen:

kwin4_effect_dialogparent:

kwin4_effect_maximize:

slidingpopups:
fadeInTime: 75
fadeOutTime: 125

slideback:

slide:

screenshot:

minimizeanimation:

glide:
duration: 175
effect: 0
angle: -90

flipswitch:
tabBox: false
tabBoxAlternative: false
duration: 100
angle: 30
xPosition: 0.33000001311302185
yPosition: 1
windowTitle: true

desktopgrid:
zoomDuration: 150
border: 10
desktopNameAlignment: 0
layoutMode: 1
customLayoutRows: 2
usePresentWindows: true

coverswitch:
animationDuration: 100
animateSwitch: true
animateStart: true
animateStop: true
reflection: true
windowTitle: true
zPosition: 900
primaryTabBox: false
secondaryTabBox: false

colorpicker:

sheet:
duration: 250

presentwindows:
layoutMode: 0
showCaptions: true
showIcons: true
doNotCloseWindows: false
ignoreMinimized: false
accuracy: 20
fillGaps: true
fadeDuration: 75
showPanel: false
leftButtonWindow: 1
rightButtonWindow: 2
middleButtonWindow: 4
leftButtonDesktop: 2
middleButtonDesktop: 0
rightButtonDesktop: 0

highlightwindow:

blur:

windowgeometry:
handlesMoves: true
handlesResizes: true

startupfeedback:
type: 1

screenedge:

kscreen: