SUMMARY
If the Krita window enters fullscreen mode on Mac by use of the green button in the titlebar rather than View > Full Screen Mode, and then View > Show Canvas Only is used, then, when Show Canvas Only is exited, fullscreen is exited as well.

STEPS TO REPRODUCE
1. Open Krita on a Mac.
2. Click the green button in the titlebar and wait for the window to go fullscreen.
3. Select the menu item View > Show Canvas Only, or use your associated keyboard shortcut.
4. Repeat step 3 so as to uncheck Show Canvas Only.

OBSERVED RESULT
In addition to exiting Canvas Only mode, the window exits fullscreen mode.

EXPECTED RESULT
When exiting Canvas Only mode, the window should return to whatever state of fullscreenitude it was in before Canvas Only mode was entered, as it does with the use of View > Full Screen Mode.

PASTE FROM BUG REPORT WINDOW
Krita

 Version: 5.1.0
 Hidpi: true

Qt

  Version (compiled): 5.12.12
  Version (loaded): 5.12.12

OS Information

  Build ABI: x86_64-little_endian-lp64
  Build CPU: x86_64
  CPU: x86_64
  Kernel Type: darwin
  Kernel Version: 18.7.0
  Pretty Productname: macOS Mojave (10.14)
  Product Type: osx
  Product Version: 10.14

Locale

  Languages: en_US
  C locale: C
  QLocale current: en
  QLocale system: en
  QTextCodec for locale: UTF-8

OpenGL Info
 
  Vendor:  "Intel Inc." 
  Renderer:  "Intel HD Graphics 4000 OpenGL Engine" 
  Version:  "4.1 INTEL-12.10.31" 
  Shading language:  "4.10" 
  Requested format:  QSurfaceFormat(version 3.2, options QFlags<QSurfaceFormat::FormatOption>(), depthBufferSize 24, redBufferSize 8, greenBufferSize 8, blueBufferSize 8, alphaBufferSize 8, stencilBufferSize 8, samples -1, swapBehavior QSurfaceFormat::DoubleBuffer, swapInterval 0, colorSpace QSurfaceFormat::DefaultColorSpace, profile  QSurfaceFormat::CoreProfile) 
  Current format:  QSurfaceFormat(version 4.1, options QFlags<QSurfaceFormat::FormatOption>(), depthBufferSize 24, redBufferSize 8, greenBufferSize 8, blueBufferSize 8, alphaBufferSize 8, stencilBufferSize 8, samples 0, swapBehavior QSurfaceFormat::DoubleBuffer, swapInterval 0, colorSpace QSurfaceFormat::DefaultColorSpace, profile  QSurfaceFormat::CoreProfile) 
     Version: 4.1
     Supports deprecated functions false 
     is OpenGL ES: false 
  supportsBufferMapping: true 
  supportsBufferInvalidation: false 
  forceDisableTextureBuffers: false 
  Extensions: 
     "GL_ARB_draw_buffers_blend" 
     "GL_APPLE_container_object_shareable" 
     "GL_APPLE_flush_render" 
     "GL_APPLE_texture_range" 
     "GL_ARB_texture_storage" 
     "GL_EXT_debug_marker" 
     "GL_ARB_shader_bit_encoding" 
     "GL_ARB_timer_query" 
     "GL_ARB_vertex_type_2_10_10_10_rev" 
     "GL_EXT_debug_label" 
     "GL_ARB_gpu_shader_fp64" 
     "GL_ARB_gpu_shader5" 
     "GL_ARB_sample_shading" 
     "GL_ARB_shading_language_include" 
     "GL_ARB_vertex_attrib_64bit" 
     "GL_EXT_texture_compression_s3tc" 
     "GL_ARB_texture_cube_map_array" 
     "GL_ARB_transform_feedback3" 
     "GL_ARB_blend_func_extended" 
     "GL_ARB_transform_feedback2" 
     "GL_ARB_occlusion_query2" 
     "GL_EXT_framebuffer_multisample_blit_scaled" 
     "GL_ARB_texture_query_lod" 
     "GL_APPLE_client_storage" 
     "GL_APPLE_object_purgeable" 
     "GL_ARB_texture_swizzle" 
     "GL_NV_texture_barrier" 
     "GL_ARB_ES2_compatibility" 
     "GL_ARB_separate_shader_objects" 
     "GL_ATI_texture_mirror_once" 
     "GL_ARB_sampler_objects" 
     "GL_ARB_explicit_attrib_location" 
     "GL_ARB_viewport_array" 
     "GL_APPLE_row_bytes" 
     "GL_ARB_tessellation_shader" 
     "GL_ARB_instanced_arrays" 
     "GL_ARB_draw_indirect" 
     "GL_EXT_texture_sRGB_decode" 
     "GL_EXT_texture_filter_anisotropic" 
     "GL_ARB_texture_rgb10_a2ui" 
     "GL_APPLE_rgb_422" 
     "GL_ARB_texture_gather" 
     "GL_ARB_shader_subroutine" 
     "GL_ARB_texture_buffer_object_rgb32" 
     "GL_ARB_internalformat_query" 

QPA OpenGL Detection Info 
  supportsDesktopGL: true 
  supportsOpenGLES: false 
  isQtPreferOpenGLES: true 

useBufferInvalidation (config option): false


Hardware Information

  GPU Acceleration: auto
  Memory: 16384 Mb
  Number of Cores: 8
  Swap Location: /private/var/folders/fn/68vtz98s1jzglybrpt5c2psc0000gn/T
  Built for: sse4.1
  Base instruction set: sse4.1
  Supported instruction sets: sse4.2 sse4.1 ssse3 sse3 sse2 

Current Settings

  Current Swap Location: /private/var/folders/fn/68vtz98s1jzglybrpt5c2psc0000gn/T
  Current Swap Location writable: true
  Undo Enabled: true
  Undo Stack Limit: 200
  Use OpenGL: true
  Use OpenGL Texture Buffer: true
  Disable Vector Optimizations: false
  Disable AVX Optimizations: false
  Canvas State: OPENGL_SUCCESS
  Autosave Interval: 420
  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: 1
	Screen: 0
		Name: Color LCD
		Depth: 24
		Scale: 2
		Physical DPI110.5
		Logical DPI72
		Physical Size: 331.005, 206.878
		Position: 0, 0
		Resolution in pixels: 1440x900
		Manufacturer: 
		Model: 
		Refresh Rate: 60


---------------------
================================================================================
SESSION: 29 Aug 2022 13:27:14 -0700. Executing /Applications/krita.app/Contents/MacOS/krita

Krita Version: 5.1.0, Qt version compiled: 5.12.12, loaded: 5.12.12. Process ID: 29706
-- -- -- -- -- -- -- --
29 Aug 2022 13:27:14 -0700: Style: macintosh. Available styles: macintosh, Windows, Fusion
29 Aug 2022 13:27:19 -0700: Creating database from scratch (database didn't exist, new schema version: 0.0.17).
29 Aug 2022 13:28:56 -0700: Importing image/png to application/x-krita. Location: /Users/miles/Downloads/unstable/unknown.png. Real location: /Users/miles/Downloads/unstable/unknown.png. Batchmode: 0
29 Aug 2022 13:28:56 -0700: Loaded image from image/png. Size: 640 * 880 pixels, 1 dpi. Color model: 8-bit integer/channel RGB/Alpha (sRGB-elle-V2-srgbtrc.icc). Layers: 2
29 Aug 2022 13:37:08 -0700: CLOSING SESSION
================================================================================
SESSION: 29 Aug 2022 13:38:05 -0700. Executing /Applications/krita.app/Contents/MacOS/krita

Krita Version: 5.1.0, Qt version compiled: 5.12.12, loaded: 5.12.12. Process ID: 29791
-- -- -- -- -- -- -- --
29 Aug 2022 13:38:05 -0700: Style: macintosh. Available styles: macintosh, Windows, Fusion
29 Aug 2022 13:38:07 -0700: Database is up to date. Version: 0.0.17, created by Krita 5.1.0, at Mon Aug 29 13:27:19 2022
29 Aug 2022 13:38:34 -0700: Importing application/x-krita to application/x-krita. Location: /Applications/krita.app/Contents/share/krita/templates/comics/.source/BD-EuroTemplate.kra. Real location: /Applications/krita.app/Contents/share/krita/templates/comics/.source/BD-EuroTemplate.kra. Batchmode: 0
29 Aug 2022 13:38:34 -0700: Loaded image from application/x-krita. Size: 2480 * 3508 pixels, 4.16667 dpi. Color model: 8-bit integer/channel RGB/Alpha (sRGB built-in). Layers: 8
29 Aug 2022 13:38:58 -0700: Importing application/x-krita to application/x-krita. Location: /Applications/krita.app/Contents/share/krita/templates/animation/.source/Anim-Jp-EN.kra. Real location: /Applications/krita.app/Contents/share/krita/templates/animation/.source/Anim-Jp-EN.kra. Batchmode: 0
29 Aug 2022 13:38:58 -0700: Loaded image from application/x-krita. Size: 1756 * 1240 pixels, 4.16667 dpi. Color model: 8-bit integer/channel RGB/Alpha (sRGB-elle-V2-srgbtrc.icc). Layers: 39
29 Aug 2022 13:39:44 -0700: Importing application/x-krita to application/x-krita. Location: /Applications/krita.app/Contents/share/krita/templates/texture/.source/Texture1024x10248bitsrgb.kra. Real location: /Applications/krita.app/Contents/share/krita/templates/texture/.source/Texture1024x10248bitsrgb.kra. Batchmode: 0
29 Aug 2022 13:39:44 -0700: Loaded image from application/x-krita. Size: 1024 * 1024 pixels, 1.38889 dpi. Color model: 8-bit integer/channel RGB/Alpha (sRGB built-in). Layers: 3

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