hi, do you happen to use windows 10 in tablet mode?

Thanks for reply. No it's just running normally on a regular laptop.

can you try to replicate this behaviour when you launch firefox in safe mode once? Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems

That was not good. Firefox went very strange and wouldn't draw its windows correctly. Whenever I went to click anything that part of the window would disappear. Eventually just little blocks of the original window left. I closed it and disabled my one add on (pop up blocker) and the problem persists. In addition (might be connected I'd guess) I can't drag a maximised firefox window onto my second screen. Or in Windows 10 just dragging a maximised screen downwards should restore it to its non-maximised size. that doesn't work with the new Firefox wither.

hm, this is all sounding quite strange. could you go to the firefox menu ≡ > help ? > troubleshooting information, copy the contents of that page and paste them here into a reply on the forum? this might give us a clue about your system/configuration...

There's sensitive info in there it seems. Username/print server etc. Is there anything more specific I could share?

i'd be particularly interested in the general & graphics sections. the rest shouldn't matter i'd think ...

Application Basics

Name: Firefox Version: 57.0 Build ID: 20171112125346 Update Channel: release User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:57.0) Gecko/20100101 Firefox/57.0 OS: Windows_NT 10.0 Multiprocess Windows: 1/1 (Enabled by default) Web Content Processes: 2/4 Stylo: true (enabled by default) Google Key: Found Mozilla Location Service Key: Found Safe Mode: false

Crash Reports for the Last 3 Days

All Crash Reports

Firefox Features

Name: Activity Stream Version: 2017.11.07.1100-7f4e3634 ID: activity-stream@mozilla.org

Name: Application Update Service Helper Version: 2.0 ID: aushelper@mozilla.org

Name: Firefox Screenshots Version: 19.2.0 ID: screenshots@mozilla.org

Name: Follow-on Search Telemetry Version: 0.9.6 ID: followonsearch@mozilla.com

Name: Form Autofill Version: 1.0 ID: formautofill@mozilla.org

Name: Multi-process staged rollout Version: 3.05 ID: e10srollout@mozilla.org

Name: Photon onboarding Version: 1.0 ID: onboarding@mozilla.org

Name: Pocket Version: 1.0.5 ID: firefox@getpocket.com

Name: Shield Recipe Client Version: 76.1 ID: shield-recipe-client@mozilla.org

Name: Web Compat Version: 1.1 ID: webcompat@mozilla.org

Extensions

Name: Adblock Plus Version: 3.0.1 Enabled: false ID: {d10d0bf8-f5b5-c8b4-a8b2-2b9879e08c5d}

Graphics

Features Compositing: Direct3D 11 (Advanced Layers) Asynchronous Pan/Zoom: wheel input enabled; scrollbar drag enabled; keyboard enabled; autoscroll enabled WebGL 1 Driver WSI Info: EGL_VENDOR: Google Inc. (adapter LUID: 0000000000007238) EGL_VERSION: 1.4 (ANGLE 2.1.0.dec065540d5f) EGL_EXTENSIONS: EGL_EXT_create_context_robustness EGL_ANGLE_d3d_share_handle_client_buffer EGL_ANGLE_d3d_texture_client_buffer EGL_ANGLE_surface_d3d_texture_2d_share_handle EGL_ANGLE_query_surface_pointer EGL_ANGLE_window_fixed_size EGL_ANGLE_keyed_mutex EGL_ANGLE_surface_orientation EGL_ANGLE_direct_composition EGL_NV_post_sub_buffer EGL_KHR_create_context EGL_EXT_device_query EGL_KHR_image EGL_KHR_image_base EGL_KHR_gl_texture_2D_image EGL_KHR_gl_texture_cubemap_image EGL_KHR_gl_renderbuffer_image EGL_KHR_get_all_proc_addresses EGL_KHR_stream EGL_KHR_stream_consumer_gltexture EGL_NV_stream_consumer_gltexture_yuv EGL_ANGLE_flexible_surface_compatibility EGL_ANGLE_stream_producer_d3d_texture_nv12 EGL_ANGLE_create_context_webgl_compatibility EGL_CHROMIUM_create_context_bind_generates_resource EGL_EXTENSIONS(nullptr): EGL_EXT_client_extensions EGL_EXT_platform_base EGL_EXT_platform_device EGL_ANGLE_platform_angle EGL_ANGLE_platform_angle_d3d EGL_ANGLE_device_creation EGL_ANGLE_device_creation_d3d11 EGL_ANGLE_experimental_present_path EGL_KHR_client_get_all_proc_addresses WebGL 1 Driver Renderer: Google Inc. -- ANGLE (Intel(R) HD Graphics 4600 Direct3D11 vs_5_0 ps_5_0) WebGL 1 Driver Version: OpenGL ES 2.0 (ANGLE 2.1.0.dec065540d5f) WebGL 1 Driver Extensions: GL_ANGLE_depth_texture GL_ANGLE_framebuffer_blit GL_ANGLE_framebuffer_multisample GL_ANGLE_instanced_arrays GL_ANGLE_lossy_etc_decode GL_ANGLE_pack_reverse_row_order GL_ANGLE_request_extension GL_ANGLE_robust_client_memory GL_ANGLE_texture_compression_dxt3 GL_ANGLE_texture_compression_dxt5 GL_ANGLE_texture_usage GL_ANGLE_translated_shader_source GL_CHROMIUM_bind_generates_resource GL_CHROMIUM_bind_uniform_location GL_CHROMIUM_copy_compressed_texture GL_CHROMIUM_copy_texture GL_CHROMIUM_sync_query GL_EXT_blend_minmax GL_EXT_color_buffer_half_float GL_EXT_debug_marker GL_EXT_discard_framebuffer GL_EXT_disjoint_timer_query GL_EXT_draw_buffers GL_EXT_frag_depth GL_EXT_map_buffer_range GL_EXT_occlusion_query_boolean GL_EXT_read_format_bgra GL_EXT_robustness GL_EXT_sRGB GL_EXT_shader_texture_lod GL_EXT_texture_compression_dxt1 GL_EXT_texture_filter_anisotropic GL_EXT_texture_format_BGRA8888 GL_EXT_texture_rg GL_EXT_texture_storage GL_EXT_unpack_subimage GL_KHR_debug GL_NV_EGL_stream_consumer_external GL_NV_fence GL_NV_pack_subimage GL_NV_pixel_buffer_object GL_OES_EGL_image GL_OES_EGL_image_external GL_OES_compressed_ETC1_RGB8_texture GL_OES_depth32 GL_OES_element_index_uint GL_OES_get_program_binary GL_OES_mapbuffer GL_OES_packed_depth_stencil GL_OES_rgb8_rgba8 GL_OES_standard_derivatives 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_OES_vertex_array_object WebGL 1 Extensions: ANGLE_instanced_arrays EXT_blend_minmax EXT_color_buffer_half_float EXT_frag_depth EXT_shader_texture_lod EXT_texture_filter_anisotropic EXT_disjoint_timer_query OES_element_index_uint OES_standard_derivatives OES_texture_float OES_texture_float_linear OES_texture_half_float OES_texture_half_float_linear OES_vertex_array_object WEBGL_color_buffer_float WEBGL_compressed_texture_s3tc WEBGL_debug_renderer_info WEBGL_debug_shaders WEBGL_depth_texture WEBGL_draw_buffers WEBGL_lose_context MOZ_WEBGL_lose_context MOZ_WEBGL_compressed_texture_s3tc MOZ_WEBGL_depth_texture WebGL 2 Driver WSI Info: EGL_VENDOR: Google Inc. (adapter LUID: 0000000000007238) EGL_VERSION: 1.4 (ANGLE 2.1.0.dec065540d5f) EGL_EXTENSIONS: EGL_EXT_create_context_robustness EGL_ANGLE_d3d_share_handle_client_buffer EGL_ANGLE_d3d_texture_client_buffer EGL_ANGLE_surface_d3d_texture_2d_share_handle EGL_ANGLE_query_surface_pointer EGL_ANGLE_window_fixed_size EGL_ANGLE_keyed_mutex EGL_ANGLE_surface_orientation EGL_ANGLE_direct_composition EGL_NV_post_sub_buffer EGL_KHR_create_context EGL_EXT_device_query EGL_KHR_image EGL_KHR_image_base EGL_KHR_gl_texture_2D_image EGL_KHR_gl_texture_cubemap_image EGL_KHR_gl_renderbuffer_image EGL_KHR_get_all_proc_addresses EGL_KHR_stream EGL_KHR_stream_consumer_gltexture EGL_NV_stream_consumer_gltexture_yuv EGL_ANGLE_flexible_surface_compatibility EGL_ANGLE_stream_producer_d3d_texture_nv12 EGL_ANGLE_create_context_webgl_compatibility EGL_CHROMIUM_create_context_bind_generates_resource EGL_EXTENSIONS(nullptr): EGL_EXT_client_extensions EGL_EXT_platform_base EGL_EXT_platform_device EGL_ANGLE_platform_angle EGL_ANGLE_platform_angle_d3d EGL_ANGLE_device_creation EGL_ANGLE_device_creation_d3d11 EGL_ANGLE_experimental_present_path EGL_KHR_client_get_all_proc_addresses WebGL 2 Driver Renderer: Google Inc. -- ANGLE (Intel(R) HD Graphics 4600 Direct3D11 vs_5_0 ps_5_0) WebGL 2 Driver Version: OpenGL ES 3.0 (ANGLE 2.1.0.dec065540d5f) WebGL 2 Driver Extensions: GL_ANGLE_depth_texture GL_ANGLE_framebuffer_blit GL_ANGLE_framebuffer_multisample GL_ANGLE_instanced_arrays GL_ANGLE_lossy_etc_decode GL_ANGLE_pack_reverse_row_order GL_ANGLE_request_extension GL_ANGLE_robust_client_memory GL_ANGLE_texture_compression_dxt3 GL_ANGLE_texture_compression_dxt5 GL_ANGLE_texture_usage GL_ANGLE_translated_shader_source GL_CHROMIUM_bind_generates_resource GL_CHROMIUM_bind_uniform_location GL_CHROMIUM_copy_compressed_texture GL_CHROMIUM_copy_texture GL_CHROMIUM_sync_query GL_EXT_blend_minmax GL_EXT_color_buffer_float GL_EXT_color_buffer_half_float GL_EXT_debug_marker GL_EXT_discard_framebuffer GL_EXT_disjoint_timer_query GL_EXT_draw_buffers GL_EXT_frag_depth GL_EXT_map_buffer_range GL_EXT_occlusion_query_boolean GL_EXT_read_format_bgra GL_EXT_robustness GL_EXT_sRGB GL_EXT_shader_texture_lod GL_EXT_texture_compression_dxt1 GL_EXT_texture_filter_anisotropic GL_EXT_texture_format_BGRA8888 GL_EXT_texture_norm16 GL_EXT_texture_rg GL_EXT_texture_storage GL_EXT_unpack_subimage GL_KHR_debug GL_NV_EGL_stream_consumer_external GL_NV_fence GL_NV_pack_subimage GL_NV_pixel_buffer_object GL_OES_EGL_image GL_OES_EGL_image_external GL_OES_EGL_image_external_essl3 GL_OES_compressed_ETC1_RGB8_texture GL_OES_depth32 GL_OES_element_index_uint GL_OES_get_program_binary GL_OES_mapbuffer GL_OES_packed_depth_stencil GL_OES_rgb8_rgba8 GL_OES_standard_derivatives 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_OES_vertex_array_object WebGL 2 Extensions: EXT_color_buffer_float EXT_texture_filter_anisotropic EXT_disjoint_timer_query OES_texture_float_linear WEBGL_compressed_texture_s3tc WEBGL_debug_renderer_info WEBGL_debug_shaders WEBGL_lose_context MOZ_WEBGL_lose_context MOZ_WEBGL_compressed_texture_s3tc Direct2D: true DirectWrite: true (10.0.10586.962) GPU #1 Active: Yes Description: Intel(R) HD Graphics 4600 Vendor ID: 0x8086 Device ID: 0x0416 Driver Version: 20.19.15.4312 Driver Date: 10-28-2015 Drivers: igdumdim64 igd10iumd64 igd10iumd64 igd12umd64 igdumdim32 igd10iumd32 igd10iumd32 igd12umd32 Subsys ID: 05bd1028 RAM: Unknown GPU #2 Active: No Description: AMD Radeon HD 8690M Vendor ID: 0x1002 Device ID: 0x6660 Driver Version: 15.200.1045.0 Driver Date: 6-22-2015 Drivers: aticfx64 aticfx64 aticfx64 amdxc64 aticfx32 aticfx32 aticfx32 amdxc32 atiumd64 atidxx64 atidxx64 atiumdag atidxx32 atidxx32 atiumdva atiumd6a atitmm64 Subsys ID: 05bd1028 RAM: 2048 Diagnostics ClearType Parameters: DISPLAY1 [ Gamma: 2.2 Pixel Structure: RGB ClearType Level: 100 Enhanced Contrast: 200 ] DISPLAY2 [ Gamma: 2.2 Pixel Structure: RGB ClearType Level: 100 Enhanced Contrast: 200 ] AzureCanvasAccelerated: 0 AzureCanvasBackend: Direct2D 1.1 AzureCanvasBackend (UI Process): skia AzureContentBackend: Direct2D 1.1 AzureContentBackend (UI Process): skia AzureFallbackCanvasBackend (UI Process): cairo GPUProcessPid: 10600 ClearType Parameters: DISPLAY1 [ Gamma: 2.2 Pixel Structure: RGB ClearType Level: 100 Enhanced Contrast: 200 ] DISPLAY2 [ Gamma: 2.2 Pixel Structure: RGB ClearType Level: 100 Enhanced Contrast: 200 ] Decision Log WEBRENDER: opt-in by default: WebRender is an opt-in feature unavailable by runtime: Build doesn't include WebRender

thanks, your graphics drivers are a bit dated - could you look if there are any updates available for them: Upgrade your graphics drivers to use hardware acceleration and WebGL

Updated the graphics drivers (via Dell website). That didn't help. So I tried installing a theme. That fixed the problem. I then removed that custom theme and chose the LIGHT theme instead of the DEFAULT theme and that fixed it too. For some reason the DEFAULT theme causes problems.

Thanks for your help.

great, thanks for reporting back with the solution you've found!