Created attachment 141083 [details]
Screenshot of wrong viewport size, note that the viewport is stuck on the bottom-left corner

SUMMARY

When moving the window between the two monitors with Win+Shift+Left/Right repeatedly, at some point the canvas OpenGL viewport appears to be sized incorrectly.

STEPS TO REPRODUCE
1. Press Win+Shift+Left and/or Win+Shift+Right repeatedly


Krita

 Version: 5.0.0-prealpha (git 4826656)
 Languages: zh_TW, zh, en_US, en, zh_TW, zh, en_US, en, zh_TW, zh, en_US, en, zh_TW, zh, en_US, en, zh_TW, zh, en_US, en
 Hidpi: true

Qt

  Version (compiled): 5.12.11
  Version (loaded): 5.12.11

OS Information

  Build ABI: x86_64-little_endian-llp64
  Build CPU: x86_64
  CPU: x86_64
  Kernel Type: winnt
  Kernel Version: 10.0.19041
  Pretty Productname: Windows 10 (10.0)
  Product Type: windows
  Product Version: 10

OpenGL Info
 
  Vendor:  "Google Inc." 
  Renderer:  "ANGLE (Intel(R) UHD Graphics 620 Direct3D11 vs_5_0 ps_5_0)" 
  Version:  "OpenGL ES 3.0 (ANGLE 2.1.0.57ea533f79a7)" 
  Shading language:  "OpenGL ES GLSL ES 3.00 (ANGLE 2.1.0.57ea533f79a7)" 
  Requested format:  QSurfaceFormat(version 3.0, options QFlags<QSurfaceFormat::FormatOption>(DeprecatedFunctions), depthBufferSize 24, redBufferSize 8, greenBufferSize 8, blueBufferSize 8, alphaBufferSize 8, stencilBufferSize 8, samples -1, swapBehavior QSurfaceFormat::DoubleBuffer, swapInterval 0, colorSpace QSurfaceFormat::DefaultColorSpace, profile  QSurfaceFormat::CompatibilityProfile) 
  Current format:    QSurfaceFormat(version 3.0, options QFlags<QSurfaceFormat::FormatOption>(), depthBufferSize 24, redBufferSize 8, greenBufferSize 8, blueBufferSize 8, alphaBufferSize 8, stencilBufferSize 8, samples 0, swapBehavior QSurfaceFormat::DefaultSwapBehavior, swapInterval 0, colorSpace QSurfaceFormat::DefaultColorSpace, profile  QSurfaceFormat::NoProfile) 
     Version: 3.0
     Supports deprecated functions false 
     is OpenGL ES: true 

QPA OpenGL Detection Info 
  supportsDesktopGL: true 
  supportsAngleD3D11: true 
  isQtPreferAngle: true 

Hardware Information

  GPU Acceleration: auto
  Memory: 24430 Mb
  Number of Cores: 8
  Swap Location: C:/Users/Alvin/AppData/Local/Temp

Current Settings

  Current Swap Location: C:/Users/Alvin/AppData/Local/Temp
  Current Swap Location writable: true
  Undo Enabled: true
  Undo Stack Limit: 30
  Use OpenGL: true
  Use OpenGL Texture Buffer: true
  Disable Vector Optimizations: false
  Disable AVX Optimizations: false
  Canvas State: OPENGL_SUCCESS
  Autosave Interval: 900
  Use Backup Files: true
  Number of Backups Kept: 1
  Backup File Suffix: ~
  Backup Location: Same Folder as the File
  Backup Location writable: false
  Use Win8 Pointer Input: false
  Use RightMiddleTabletButton Workaround: false
  Levels of Detail Enabled: false
  Use Zip64: false


Display Information
Number of screens: 2
	Screen: 0
		Name: \\.\DISPLAY1
		Depth: 32
		Scale: 1.5
		Resolution in pixels: 1707x960
		Manufacturer: 
		Model: 
		Refresh Rate: 60
	Screen: 1
		Name: \\.\DISPLAY2
		Depth: 32
		Scale: 1
		Resolution in pixels: 1920x1080
		Manufacturer: 
		Model: 
		Refresh Rate: 60