Version 55.0.2883.105 (64-bit)
Platform 8872.76.0 (Official Build) stable-channel samus
ARC Version 3617689
Firmware Google_Samus.6300.174.0

What steps will reproduce the problem?
(1) drag a window below the shelf
(2) observe the white area that appears below

What is the expected result?
window hidden behind shelf

What happens instead?
Window partially hidden behind shelf with a 1 line of pixel appearing below it.
See attached video 



Just in-case this is a GPU issue and not a Shelf, here is the paste of about:gpu

Graphics Feature Status
Canvas: Hardware accelerated
Flash: Hardware accelerated
Flash Stage3D: Hardware accelerated
Flash Stage3D Baseline profile: Hardware accelerated
Compositing: Hardware accelerated
Multiple Raster Threads: Enabled
Native GpuMemoryBuffers: Hardware accelerated
Panel Fitting: Unavailable
Rasterization: Software only. Hardware acceleration disabled
Video Decode: Hardware accelerated
Video Encode: Hardware accelerated
VPx Video Decode: Hardware accelerated
WebGL: Hardware accelerated
Driver Bug Workarounds
clear_uniforms_before_first_program_use
count_all_in_varyings_packing
disable_discard_framebuffer
msaa_is_slow
scalarize_vec_and_mat_constructor_args
Problems Detected
Chrome OS panel fitting is only supported for Intel IVB and SNB Graphics Controllers
Disabled Features: panel_fitting
Framebuffer discarding causes jumpy scrolling on Mali drivers: 301988
Applied Workarounds: disable_discard_framebuffer
Clear uniforms before first program use on all platforms: 124764, 349137
Applied Workarounds: clear_uniforms_before_first_program_use
Mesa drivers in ChromeOS handle varyings without static use incorrectly: 333885
Applied Workarounds: count_all_in_varyings_packing
Always rewrite vec/mat constructors to be consistent: 398694
Applied Workarounds: scalarize_vec_and_mat_constructor_args
On Intel GPUs MSAA performance is not acceptable for GPU rasterization: 527565
Applied Workarounds: msaa_is_slow
Accelerated rasterization has been disabled, either via blacklist, about:flags or the command line.
Disabled Features: rasterization
Version Information
Data exported	2/27/2017, 7:27:26 PM
Chrome version	Chrome/55.0.2883.105
Operating system	Linux 3.14.0
Software rendering list version	11.17
Driver bug list version	9.15
ANGLE commit id	4d208abb1926
2D graphics backend	Skia/55 0
Command Line Args	--ppapi-flash-path=/opt/google/chrome/pepper/libpepflashplayer.so --ppapi-flash-version=24.0.0.186 --ui-prioritize-in-gpu-process --use-gl=egl --enable-native-gpu-memory-buffers --gpu-sandbox-failures-fatal=yes --arc-available --enable-arc --enable-logging --log-level=1 --use-cras --enable-wayland-server --user-data-dir=/home/chronos --max-unused-resource-memory-usage-percentage=5 --login-profile=user --enable-natural-scroll-default --has-chromeos-keyboard --default-wallpaper-large=/usr/share/chromeos-assets/wallpaper/default_large.jpg --default-wallpaper-small=/usr/share/chromeos-assets/wallpaper/default_small.jpg --child-wallpaper-large=/usr/share/chromeos-assets/wallpaper/child_large.jpg --child-wallpaper-small=/usr/share/chromeos-assets/wallpaper/child_small.jpg --guest-wallpaper-large=/usr/share/chromeos-assets/wallpaper/guest_large.jpg --guest-wallpaper-small=/usr/share/chromeos-assets/wallpaper/guest_small.jpg --enable-prefixed-encrypted-media --enterprise-enrollment-initial-modulus=15 --enterprise-enrollment-modulus-limit=19 --vmodule=screen_locker=2,webui_screen_locker=2,lock_state_controller=2,webui_login_view=2,power_button_observer=2,*ui/display/chromeos*=1,*ash/display*=1,*ui/ozone*=1,*zygote*=1,*plugin*=2,*chromeos/login/*=1,*arc/*=1 --login-user=omrilio@google.com --login-profile=919a347f8188c1963a3fd0e6686c385868780733 --flag-switches-begin --javascript-harmony --secondary-ui-md --flag-switches-end
Driver Information
Initialization time	22
In-process GPU	false
Sandboxed	true
GPU0	VENDOR = 0x8086, DEVICE= 0x1616
Optimus	false
AMD switchable	false
Driver vendor	Mesa
Driver version	12.1.0
Driver date	
Pixel shader version	3.10
Vertex shader version	3.10
Max. MSAA samples	8
Machine model name	
Machine model version	
GL_VENDOR	Intel Open Source Technology Center
GL_RENDERER	Mesa DRI Intel(R) HD Graphics 5500 (Broadwell GT2)
GL_VERSION	OpenGL ES 3.1 Mesa 12.1.0-devel (git-b010fa8)
GL_EXTENSIONS	GL_EXT_blend_minmax GL_EXT_multi_draw_arrays GL_EXT_texture_filter_anisotropic GL_EXT_texture_compression_dxt1 GL_EXT_texture_format_BGRA8888 GL_OES_compressed_ETC1_RGB8_texture GL_OES_depth24 GL_OES_element_index_uint GL_OES_fbo_render_mipmap GL_OES_mapbuffer GL_OES_rgb8_rgba8 GL_OES_standard_derivatives GL_OES_stencil8 GL_OES_texture_3D GL_OES_texture_float GL_OES_texture_float_linear GL_OES_texture_half_float GL_OES_texture_half_float_linear GL_OES_texture_npot GL_EXT_texture_sRGB_decode GL_OES_EGL_image GL_OES_depth_texture GL_OES_packed_depth_stencil GL_EXT_texture_type_2_10_10_10_REV GL_OES_get_program_binary GL_APPLE_texture_max_level GL_EXT_discard_framebuffer GL_EXT_read_format_bgra GL_NV_fbo_color_attachments GL_OES_EGL_image_external GL_OES_EGL_sync GL_OES_vertex_array_object GL_ANGLE_texture_compression_dxt3 GL_ANGLE_texture_compression_dxt5 GL_EXT_texture_rg GL_EXT_unpack_subimage GL_NV_draw_buffers GL_NV_read_buffer GL_NV_read_depth GL_NV_read_depth_stencil GL_NV_read_stencil GL_EXT_draw_buffers GL_EXT_map_buffer_range GL_KHR_debug GL_KHR_robustness GL_OES_depth_texture_cube_map GL_OES_surfaceless_context GL_EXT_color_buffer_float GL_EXT_separate_shader_objects GL_EXT_shader_integer_mix GL_EXT_copy_image GL_EXT_draw_buffers_indexed GL_EXT_draw_elements_base_vertex GL_EXT_gpu_shader5 GL_EXT_polygon_offset_clamp GL_EXT_shader_io_blocks GL_EXT_texture_border_clamp GL_EXT_texture_buffer GL_KHR_context_flush_control GL_KHR_robust_buffer_access_behavior GL_OES_copy_image GL_OES_draw_buffers_indexed GL_OES_draw_elements_base_vertex GL_OES_gpu_shader5 GL_OES_sample_shading GL_OES_sample_variables GL_OES_shader_io_blocks GL_OES_shader_multisample_interpolation GL_OES_texture_border_clamp GL_OES_texture_buffer GL_OES_texture_stencil8 GL_OES_texture_storage_multisample_2d_array GL_EXT_blend_func_extended GL_EXT_buffer_storage GL_EXT_shader_samples_identical GL_OES_shader_image_atomic GL_EXT_clip_cull_distance
Disabled Extensions	
Window system binding vendor	Mesa Project
Window system binding version	1.4 (DRI2)
Window system binding extensions	EGL_EXT_create_context_robustness EGL_EXT_image_dma_buf_import EGL_KHR_create_context EGL_KHR_fence_sync EGL_KHR_get_all_proc_addresses EGL_KHR_gl_renderbuffer_image EGL_KHR_gl_texture_2D_image EGL_KHR_gl_texture_cubemap_image EGL_KHR_image_base EGL_KHR_reusable_sync EGL_KHR_surfaceless_context EGL_KHR_wait_sync EGL_MESA_configless_context EGL_MESA_drm_image EGL_MESA_image_dma_buf_export
Direct rendering	Yes
Reset notification strategy	0x0000
GPU process crash count	0
Compositor Information
Tile Update Mode	One-copy
Partial Raster	Enabled
GpuMemoryBuffers Status
ATC	Software only
ATCIA	Software only
DXT1	Software only
DXT5	Software only
ETC1	Software only
R_8	GPU_READ_CPU_READ_WRITE, GPU_READ_CPU_READ_WRITE_PERSISTENT
RG_88	GPU_READ_CPU_READ_WRITE, GPU_READ_CPU_READ_WRITE_PERSISTENT
BGR_565	GPU_READ
RGBA_4444	Software only
RGBX_8888	GPU_READ, SCANOUT
RGBA_8888	GPU_READ
BGRX_8888	GPU_READ, SCANOUT
BGRA_8888	GPU_READ, GPU_READ_CPU_READ_WRITE, GPU_READ_CPU_READ_WRITE_PERSISTENT
YVU_420	GPU_READ
YUV_420_BIPLANAR	Software only
UYVY_422	Software only
Log Messages
[14419:14425:0226/212731:ERROR:interface_registry.cc(99)] : Capability spec prevented service service:content_browser from binding interface: mojom::ResourceUsageReporter
[14419:14426:0226/212731:VERBOSE1:drm_device_manager.cc(54)] : Could not initialize DRM device for /sys/devices/platform/vgem/drm/card1
[14419:14426:0226/212732:VERBOSE1:drm_display.cc(102)] : DRM configuring: device=/sys/devices/pci0000:00/0000:00:02.0/drm/card0 crtc=20 connector=29 origin=0,0 size=2560x1700
[14419:14426:0226/220500:WARNING:screen_manager.cc(101)] : Display controller (crtc=20) already present.
[14419:14426:0226/220500:VERBOSE1:drm_display.cc(102)] : DRM configuring: device=/sys/devices/pci0000:00/0000:00:02.0/drm/card0 crtc=20 connector=29 origin=0,0 size=0x0
[14419:14426:0226/221521:WARNING:screen_manager.cc(101)] : Display controller (crtc=20) already present.
[14419:14426:0226/221521:VERBOSE1:drm_display.cc(102)] : DRM configuring: device=/sys/devices/pci0000:00/0000:00:02.0/drm/card0 crtc=20 connector=29 origin=0,0 size=2560x1700
[14419:14426:0226/221522:WARNING:screen_manager.cc(101)] : Display controller (crtc=20) already present.
[14419:14426:0226/221522:VERBOSE1:drm_display.cc(102)] : DRM configuring: device=/sys/devices/pci0000:00/0000:00:02.0/drm/card0 crtc=20 connector=29 origin=0,0 size=2560x1700
[14419:14419:0226/231703:ERROR:gles2_cmd_decoder.cc(16349)] : [.DisplayCompositor-0x127e9d843500]GL ERROR :GL_INVALID_OPERATION : glCreateAndConsumeTextureCHROMIUM: invalid mailbox name
[14419:14426:0226/232008:WARNING:screen_manager.cc(101)] : Display controller (crtc=20) already present.
[14419:14426:0226/232008:VERBOSE1:drm_display.cc(102)] : DRM configuring: device=/sys/devices/pci0000:00/0000:00:02.0/drm/card0 crtc=20 connector=29 origin=0,0 size=0x0
[14419:14426:0226/232532:WARNING:screen_manager.cc(101)] : Display controller (crtc=20) already present.
[14419:14426:0226/232532:VERBOSE1:drm_display.cc(102)] : DRM configuring: device=/sys/devices/pci0000:00/0000:00:02.0/drm/card0 crtc=20 connector=29 origin=0,0 size=2560x1700
[14419:14426:0226/232537:WARNING:screen_manager.cc(101)] : Display controller (crtc=20) already present.
[14419:14426:0226/232537:VERBOSE1:drm_display.cc(102)] : DRM configuring: device=/sys/devices/pci0000:00/0000:00:02.0/drm/card0 crtc=20 connector=29 origin=0,0 size=0x0
[14419:14426:0227/123653:WARNING:screen_manager.cc(101)] : Display controller (crtc=20) already present.
[14419:14426:0227/123653:VERBOSE1:drm_display.cc(102)] : DRM configuring: device=/sys/devices/pci0000:00/0000:00:02.0/drm/card0 crtc=20 connector=29 origin=0,0 size=2560x1700
[14419:14426:0227/124357:WARNING:screen_manager.cc(101)] : Display controller (crtc=20) already present.
[14419:14426:0227/124357:VERBOSE1:drm_display.cc(102)] : DRM configuring: device=/sys/devices/pci0000:00/0000:00:02.0/drm/card0 crtc=20 connector=29 origin=0,0 size=0x0
[14419:14426:0227/133005:WARNING:screen_manager.cc(101)] : Display controller (crtc=20) already present.
[14419:14426:0227/133005:VERBOSE1:drm_display.cc(102)] : DRM configuring: device=/sys/devices/pci0000:00/0000:00:02.0/drm/card0 crtc=20 connector=29 origin=0,0 size=2560x1700
[14419:14426:0227/140826:WARNING:screen_manager.cc(101)] : Display controller (crtc=20) already present.
[14419:14426:0227/140826:VERBOSE1:drm_display.cc(102)] : DRM configuring: device=/sys/devices/pci0000:00/0000:00:02.0/drm/card0 crtc=20 connector=29 origin=0,0 size=0x0
[14419:14426:0227/142313:WARNING:screen_manager.cc(101)] : Display controller (crtc=20) already present.
[14419:14426:0227/142313:VERBOSE1:drm_display.cc(102)] : DRM configuring: device=/sys/devices/pci0000:00/0000:00:02.0/drm/card0 crtc=20 connector=29 origin=0,0 size=2560x1700
[14419:14426:0227/144137:WARNING:screen_manager.cc(101)] : Display controller (crtc=20) already present.
[14419:14426:0227/144137:VERBOSE1:drm_display.cc(102)] : DRM configuring: device=/sys/devices/pci0000:00/0000:00:02.0/drm/card0 crtc=20 connector=29 origin=0,0 size=0x0
[14419:14426:0227/145108:WARNING:screen_manager.cc(101)] : Display controller (crtc=20) already present.
[14419:14426:0227/145108:VERBOSE1:drm_display.cc(102)] : DRM configuring: device=/sys/devices/pci0000:00/0000:00:02.0/drm/card0 crtc=20 connector=29 origin=0,0 size=2560x1700
[14419:14426:0227/151714:WARNING:screen_manager.cc(101)] : Display controller (crtc=20) already present.
[14419:14426:0227/151714:VERBOSE1:drm_display.cc(102)] : DRM configuring: device=/sys/devices/pci0000:00/0000:00:02.0/drm/card0 crtc=20 connector=29 origin=0,0 size=0x0
[14419:14426:0227/154257:WARNING:screen_manager.cc(101)] : Display controller (crtc=20) already present.
[14419:14426:0227/154257:VERBOSE1:drm_display.cc(102)] : DRM configuring: device=/sys/devices/pci0000:00/0000:00:02.0/drm/card0 crtc=20 connector=29 origin=0,0 size=2560x1700
[14419:14426:0227/154258:WARNING:screen_manager.cc(101)] : Display controller (crtc=20) already present.
[14419:14426:0227/154258:VERBOSE1:drm_display.cc(102)] : DRM configuring: device=/sys/devices/pci0000:00/0000:00:02.0/drm/card0 crtc=20 connector=29 origin=0,0 size=2560x1700
[14419:14426:0227/155519:WARNING:screen_manager.cc(101)] : Display controller (crtc=20) already present.
[14419:14426:0227/155519:VERBOSE1:drm_display.cc(102)] : DRM configuring: device=/sys/devices/pci0000:00/0000:00:02.0/drm/card0 crtc=20 connector=29 origin=0,0 size=0x0
[14419:14426:0227/161357:WARNING:screen_manager.cc(101)] : Display controller (crtc=20) already present.
[14419:14426:0227/161357:VERBOSE1:drm_display.cc(102)] : DRM configuring: device=/sys/devices/pci0000:00/0000:00:02.0/drm/card0 crtc=20 connector=29 origin=0,0 size=2560x1700
[14419:14426:0227/161358:WARNING:screen_manager.cc(101)] : Display controller (crtc=20) already present.
[14419:14426:0227/161358:VERBOSE1:drm_display.cc(102)] : DRM configuring: device=/sys/devices/pci0000:00/0000:00:02.0/drm/card0 crtc=20 connector=29 origin=0,0 size=2560x1700
[14419:14426:0227/170019:WARNING:screen_manager.cc(101)] : Display controller (crtc=20) already present.
[14419:14426:0227/170019:VERBOSE1:drm_display.cc(102)] : DRM configuring: device=/sys/devices/pci0000:00/0000:00:02.0/drm/card0 crtc=20 connector=29 origin=0,0 size=0x0
[14419:14426:0227/170206:WARNING:screen_manager.cc(101)] : Display controller (crtc=20) already present.
[14419:14426:0227/170206:VERBOSE1:drm_display.cc(102)] : DRM configuring: device=/sys/devices/pci0000:00/0000:00:02.0/drm/card0 crtc=20 connector=29 origin=0,0 size=2560x1700
[14419:14426:0227/170207:WARNING:screen_manager.cc(101)] : Display controller (crtc=20) already present.
[14419:14426:0227/170207:VERBOSE1:drm_display.cc(102)] : DRM configuring: device=/sys/devices/pci0000:00/0000:00:02.0/drm/card0 crtc=20 connector=29 origin=0,0 size=2560x1700
[14419:14426:0227/170256:WARNING:screen_manager.cc(101)] : Display controller (crtc=20) already present.
[14419:14426:0227/170257:VERBOSE1:drm_display.cc(102)] : DRM configuring: device=/sys/devices/pci0000:00/0000:00:02.0/drm/card0 crtc=20 connector=29 origin=0,0 size=0x0
[14419:14426:0227/183438:WARNING:screen_manager.cc(101)] : Display controller (crtc=20) already present.
[14419:14426:0227/183438:VERBOSE1:drm_display.cc(102)] : DRM configuring: device=/sys/devices/pci0000:00/0000:00:02.0/drm/card0 crtc=20 connector=29 origin=0,0 size=2560x1700
[14419:14426:0227/183439:WARNING:screen_manager.cc(101)] : Display controller (crtc=20) already present.
[14419:14426:0227/183439:VERBOSE1:drm_display.cc(102)] : DRM configuring: device=/sys/devices/pci0000:00/0000:00:02.0/drm/card0 crtc=20 connector=29 origin=0,0 size=2560x1700
[14419:14426:0227/184147:WARNING:screen_manager.cc(101)] : Display controller (crtc=20) already present.
[14419:14426:0227/184147:VERBOSE1:drm_display.cc(102)] : DRM configuring: device=/sys/devices/pci0000:00/0000:00:02.0/drm/card0 crtc=20 connector=29 origin=0,0 size=0x0
[14419:14426:0227/190613:WARNING:screen_manager.cc(101)] : Display controller (crtc=20) already present.
[14419:14426:0227/190613:VERBOSE1:drm_display.cc(102)] : DRM configuring: device=/sys/devices/pci0000:00/0000:00:02.0/drm/card0 crtc=20 connector=29 origin=0,0 size=2560x1700
[14419:14426:0227/190615:WARNING:screen_manager.cc(101)] : Display controller (crtc=20) already present.
[14419:14426:0227/190615:VERBOSE1:drm_display.cc(102)] : DRM configuring: device=/sys/devices/pci0000:00/0000:00:02.0/drm/card0 crtc=20 connector=29 origin=0,0 size=2560x1700
 

Deleted: test (1).webm 9.8 MB

	test (1).webm 9.8 MB View Download