Lightroom Classic - Shift-click behavior of brush is failing

My LRC System Info:

Lightroom Classic version: 15.2.1 [ 202603161217-0bf813d9 ]
License: Creative Cloud
Language setting: en
Operating system: Windows 11 - Home Premium Edition
Version: 11.0.26200
Application architecture: x64
System architecture: x64
Logical processor count: 20
Processor speed: 3,8GHz
SqLite Version: 3.36.0
Adobe GSDK Version: 1.4.0.212

CPU Utilisation: 1,0%
Power Source: Plugged In
Built-in memory: 65047,6 MB
Dedicated GPU memory used by Lightroom: 7607,7MB / 16107,0MB (47%)
Real memory available to Lightroom: 65047,6 MB
Real memory used by Lightroom: 5550,7 MB (8,5%)
Virtual memory used by Lightroom: 13966,5 MB
GDI objects count: 1070
USER objects count: 4019
Process handles count: 5177
Memory cache size: 1527,5MB
Internal Camera Raw version: 18.2.2 [ 2512 ]
Maximum thread count used by Camera Raw: 5
Camera Raw SIMD optimization: SSE2,AVX,AVX2
Camera Raw virtual memory: 756MB / 32523MB (2%)
Camera Raw real memory: 758MB / 65047MB (1%)

Cache1: 
Final1- RAM:212,0MB, VRAM:862,0MB, DSCF6604.RAF
NT- RAM:212,0MB, VRAM:862,0MB, Combined:1074,0MB

Cache2: 
m:1527,5MB, n:204,1MB

U-main: 162,0MB

System DPI setting: 120 DPI
Desktop composition enabled: Yes
Standard Preview Size: 2560 pixels
Displays: 1) 2560x1080
Input types: Multitouch: No, Integrated touch: No, Integrated pen: No, External touch: No, External pen: Yes, Keyboard: No

Graphics Processor Info: 
DirectX: NVIDIA GeForce RTX 4060 Ti (32.0.15.9579)
Init State: GPU for Export supported by default
User Preference: GPU for Image Processing Enabled
Enable HDR in Library: OFF
GPU for Preview Generation: Auto (S5_15)

Application folder: C:\Program Files\Adobe\Adobe Lightroom Classic
Library Path: D:\LightRoom\LightroomCatalogs\2024_Divers\2024_Divers-v13-3.lrcat
Settings Folder: C:\Users\Bob\AppData\Roaming\Adobe\Lightroom

Installed Plugins: 
1) AdobeStock
2) Aurora HDR
3) Export to Photomatix Pro
4) Flickr
5) HDR Efex Pro 2
6) Iridient X-Transformer
7) jf Metadata Wrangler
8) LensTagger Exif Tool
9) Luminar 3
10) ON1 Photo RAW 2019
11) ON1 Resize 2019

Config.lua flags: 

Adapter #1: Vendor : 10de
    Device : 2803
    Subsystem : 13ec196e
    Revision : a1
    Video Memory : 16107
Adapter #2: Vendor : 1414
    Device : 8c
    Subsystem : 0
    Revision : 0
    Video Memory : 0
AudioDeviceIOBlockSize: 1024
AudioDeviceName: System Default - LG ULTRAWIDE (NVIDIA High Definition Audio)
AudioDeviceNumberOfChannels: 2
AudioDeviceSampleRate: 48000
Build: LR5x34
Direct2DEnabled: false
GL_ACCUM_ALPHA_BITS: 16
GL_ACCUM_BLUE_BITS: 16
GL_ACCUM_GREEN_BITS: 16
GL_ACCUM_RED_BITS: 16
GL_ALPHA_BITS: 0
GL_BLUE_BITS: 8
GL_DEPTH_BITS: 24
GL_GREEN_BITS: 8
GL_MAX_3D_TEXTURE_SIZE: 16384
GL_MAX_TEXTURE_SIZE: 32768
GL_MAX_TEXTURE_UNITS: 4
GL_MAX_VIEWPORT_DIMS: 32768,32768
GL_RED_BITS: 8
GL_RENDERER: NVIDIA GeForce RTX 4060 Ti/PCIe/SSE2
GL_SHADING_LANGUAGE_VERSION: 4.60 NVIDIA
GL_STENCIL_BITS: 8
GL_VENDOR: NVIDIA Corporation
GL_VERSION: 4.6.0 NVIDIA 595.79
GPUDeviceEnabled: false
OGLEnabled: true
GL_EXTENSIONS: GL_AMD_multi_draw_indirect GL_AMD_seamless_cubemap_per_texture GL_AMD_vertex_shader_viewport_index GL_AMD_vertex_shader_layer GL_ARB_arrays_of_arrays GL_ARB_base_instance GL_ARB_bindless_texture GL_ARB_blend_func_extended GL_ARB_buffer_storage GL_ARB_clear_buffer_object GL_ARB_clear_texture GL_ARB_clip_control GL_ARB_color_buffer_float GL_ARB_compatibility GL_ARB_compressed_texture_pixel_storage GL_ARB_conservative_depth GL_ARB_compute_shader GL_ARB_compute_variable_group_size GL_ARB_conditional_render_inverted GL_ARB_copy_buffer GL_ARB_copy_image GL_ARB_cull_distance GL_ARB_debug_output GL_ARB_depth_buffer_float GL_ARB_depth_clamp GL_ARB_depth_texture GL_ARB_derivative_control GL_ARB_direct_state_access GL_ARB_draw_buffers GL_ARB_draw_buffers_blend GL_ARB_draw_indirect GL_ARB_draw_elements_base_vertex GL_ARB_draw_instanced GL_ARB_enhanced_layouts GL_ARB_ES2_compatibility GL_ARB_ES3_compatibility GL_ARB_ES3_1_compatibility GL_ARB_ES3_2_compatibility GL_ARB_explicit_attrib_location GL_ARB_explicit_uniform_location GL_ARB_fragment_coord_conventions GL_ARB_fragment_layer_viewport GL_ARB_fragment_program GL_ARB_fragment_program_shadow GL_ARB_fragment_shader GL_ARB_fragment_shader_interlock GL_ARB_framebuffer_no_attachments GL_ARB_framebuffer_object GL_ARB_framebuffer_sRGB GL_ARB_geometry_shader4 GL_ARB_get_program_binary GL_ARB_get_texture_sub_image GL_ARB_gl_spirv GL_ARB_gpu_shader5 GL_ARB_gpu_shader_fp64 GL_ARB_gpu_shader_int64 GL_ARB_half_float_pixel GL_ARB_half_float_vertex GL_ARB_imaging GL_ARB_indirect_parameters GL_ARB_instanced_arrays GL_ARB_internalformat_query GL_ARB_internalformat_query2 GL_ARB_invalidate_subdata GL_ARB_map_buffer_alignment GL_ARB_map_buffer_range GL_ARB_multi_bind GL_ARB_multi_draw_indirect GL_ARB_multisample GL_ARB_multitexture GL_ARB_occlusion_query GL_ARB_occlusion_query2 GL_ARB_parallel_shader_compile GL_ARB_pipeline_statistics_query GL_ARB_pixel_buffer_object GL_ARB_point_parameters GL_ARB_point_sprite GL_ARB_polygon_offset_clamp GL_ARB_post_depth_coverage GL_ARB_program_interface_query GL_ARB_provoking_vertex GL_ARB_query_buffer_object GL_ARB_robust_buffer_access_behavior GL_ARB_robustness GL_ARB_sample_locations GL_ARB_sample_shading GL_ARB_sampler_objects GL_ARB_seamless_cube_map GL_ARB_seamless_cubemap_per_texture GL_ARB_separate_shader_objects GL_ARB_shader_atomic_counter_ops GL_ARB_shader_atomic_counters GL_ARB_shader_ballot GL_ARB_shader_bit_encoding GL_ARB_shader_clock GL_ARB_shader_draw_parameters GL_ARB_shader_group_vote GL_ARB_shader_image_load_store GL_ARB_shader_image_size GL_ARB_shader_objects GL_ARB_shader_precision GL_ARB_shader_storage_buffer_object GL_ARB_shader_subroutine GL_ARB_shader_texture_image_samples GL_ARB_shader_texture_lod GL_ARB_shading_language_100 GL_ARB_shader_viewport_layer_array GL_ARB_shading_language_420pack GL_ARB_shading_language_include GL_ARB_shading_language_packing GL_ARB_shadow GL_ARB_sparse_buffer GL_ARB_sparse_texture GL_ARB_sparse_texture2 GL_ARB_sparse_texture_clamp GL_ARB_spirv_extensions GL_ARB_stencil_texturing GL_ARB_sync GL_ARB_tessellation_shader GL_ARB_texture_barrier GL_ARB_texture_border_clamp GL_ARB_texture_buffer_object GL_ARB_texture_buffer_object_rgb32 GL_ARB_texture_buffer_range GL_ARB_texture_compression GL_ARB_texture_compression_bptc GL_ARB_texture_compression_rgtc GL_ARB_texture_cube_map GL_ARB_texture_cube_map_array GL_ARB_texture_env_add GL_ARB_texture_env_combine GL_ARB_texture_env_crossbar GL_ARB_texture_env_dot3 GL_ARB_texture_filter_anisotropic GL_ARB_texture_filter_minmax GL_ARB_texture_float GL_ARB_texture_gather GL_ARB_texture_mirror_clamp_to_edge GL_ARB_texture_mirrored_repeat GL_ARB_texture_multisample GL_ARB_texture_non_power_of_two GL_ARB_texture_query_levels GL_ARB_texture_query_lod GL_ARB_texture_rectangle GL_ARB_texture_rg GL_ARB_texture_rgb10_a2ui GL_ARB_texture_stencil8 GL_ARB_texture_storage GL_ARB_texture_storage_multisample GL_ARB_texture_swizzle GL_ARB_texture_view GL_ARB_timer_query GL_ARB_transform_feedback2 GL_ARB_transform_feedback3 GL_ARB_transform_feedback_instanced GL_ARB_transform_feedback_overflow_query GL_ARB_transpose_matrix GL_ARB_uniform_buffer_object GL_ARB_vertex_array_bgra GL_ARB_vertex_array_object GL_ARB_vertex_attrib_64bit GL_ARB_vertex_attrib_binding GL_ARB_vertex_buffer_object GL_ARB_vertex_program GL_ARB_vertex_shader GL_ARB_vertex_type_10f_11f_11f_rev GL_ARB_vertex_type_2_10_10_10_rev GL_ARB_viewport_array GL_ARB_window_pos GL_ATI_draw_buffers GL_ATI_texture_float GL_ATI_texture_mirror_once GL_S3_s3tc GL_EXT_texture_env_add GL_EXT_abgr GL_EXT_bgra GL_EXT_bindable_uniform GL_EXT_blend_color GL_EXT_blend_equation_separate GL_EXT_blend_func_separate GL_EXT_blend_minmax GL_EXT_blend_subtract GL_EXT_compiled_vertex_array GL_EXT_Cg_shader GL_EXT_depth_bounds_test GL_EXT_direct_state_access GL_EXT_draw_buffers2 GL_EXT_draw_instanced GL_EXT_draw_range_elements GL_EXT_fog_coord GL_EXT_framebuffer_blit GL_EXT_framebuffer_multisample GL_EXTX_framebuffer_mixed_formats GL_EXT_framebuffer_multisample_blit_scaled GL_EXT_framebuffer_object GL_EXT_framebuffer_sRGB GL_EXT_geometry_shader4 GL_EXT_gpu_program_parameters GL_EXT_gpu_shader4 GL_EXT_multi_draw_arrays GL_EXT_multiview_texture_multisample GL_EXT_multiview_timer_query GL_EXT_packed_depth_stencil GL_EXT_packed_float GL_EXT_packed_pixels GL_EXT_pixel_buffer_object GL_EXT_point_parameters GL_EXT_polygon_offset_clamp GL_EXT_post_depth_coverage GL_EXT_provoking_vertex GL_EXT_raster_multisample GL_EXT_rescale_normal GL_EXT_secondary_color GL_EXT_separate_shader_objects GL_EXT_separate_specular_color GL_EXT_shader_image_load_formatted GL_EXT_shader_image_load_store GL_EXT_shader_integer_mix GL_EXT_shadow_funcs GL_EXT_sparse_texture2 GL_EXT_stencil_two_side GL_EXT_stencil_wrap GL_EXT_texture3D GL_EXT_texture_array GL_EXT_texture_buffer_object GL_EXT_texture_compression_dxt1 GL_EXT_texture_compression_latc GL_EXT_texture_compression_rgtc GL_EXT_texture_compression_s3tc GL_EXT_texture_cube_map GL_EXT_texture_edge_clamp GL_EXT_texture_env_combine GL_EXT_texture_env_dot3 GL_EXT_texture_filter_anisotropic GL_EXT_texture_filter_minmax GL_EXT_texture_integer GL_EXT_texture_lod GL_EXT_texture_lod_bias GL_EXT_texture_mirror_clamp GL_EXT_texture_object GL_EXT_texture_shadow_lod GL_EXT_texture_shared_exponent GL_EXT_texture_sRGB GL_EXT_texture_sRGB_R8 GL_EXT_texture_sRGB_decode GL_EXT_texture_storage GL_EXT_texture_swizzle GL_EXT_timer_query GL_EXT_transform_feedback2 GL_EXT_vertex_array GL_EXT_vertex_array_bgra GL_EXT_vertex_attrib_64bit GL_EXT_window_rectangles GL_EXT_import_sync_object GL_IBM_rasterpos_clip GL_IBM_texture_mirrored_repeat GL_KHR_context_flush_control GL_KHR_debug GL_EXT_memory_object GL_EXT_memory_object_win32 GL_NV_memory_object_sparse GL_EXT_win32_keyed_mutex GL_KHR_parallel_shader_compile GL_KHR_no_error GL_KHR_robust_buffer_access_behavior GL_KHR_robustness GL_EXT_semaphore GL_EXT_semaphore_win32 GL_NV_timeline_semaphore GL_KHR_shader_subgroup GL_KTX_buffer_region GL_NV_alpha_to_coverage_dither_control GL_NV_bindless_multi_draw_indirect GL_NV_bindless_multi_draw_indirect_count GL_NV_bindless_texture GL_NV_blend_equation_advanced GL_NV_blend_equation_advanced_coherent GL_NVX_blend_equation_advanced_multi_draw_buffers GL_NV_blend_minmax_factor GL_NV_blend_square GL_NV_clip_space_w_scaling GL_NV_command_list GL_NV_compute_program5 GL_NV_compute_shader_derivatives GL_NV_conditional_render GL_NV_conservative_raster GL_NV_conservative_raster_dilate GL_NV_conservative_raster_pre_snap GL_NV_conservative_raster_pre_snap_triangles GL_NV_conservative_raster_underestimation GL_NV_copy_depth_to_color GL_NV_copy_image GL_NV_depth_buffer_float GL_NV_depth_clamp GL_NV_draw_texture GL_NV_draw_vulkan_image GL_NV_ES1_1_compatibility GL_NV_ES3_1_compatibility GL_NV_explicit_multisample GL_NV_feature_query GL_NV_fence GL_NV_fill_rectangle GL_NV_float_buffer GL_NV_fog_distance 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GL_NV_representative_fragment_test GL_NV_sample_locations GL_NV_sample_mask_override_coverage GL_NV_scissor_exclusive GL_NV_shader_atomic_counters GL_NV_shader_atomic_float GL_NV_shader_atomic_float64 GL_NV_shader_atomic_fp16_vector GL_NV_shader_atomic_int64 GL_NV_shader_buffer_load GL_NV_shader_storage_buffer_object GL_NV_shader_subgroup_partitioned GL_NV_shader_texture_footprint GL_NV_shading_rate_image GL_NV_stereo_view_rendering GL_NV_texgen_reflection GL_NV_texture_barrier GL_NV_texture_compression_vtc GL_NV_texture_dirty_tile_map GL_NV_texture_env_combine4 GL_NV_texture_multisample GL_NV_texture_rectangle GL_NV_texture_rectangle_compressed GL_NV_texture_shader GL_NV_texture_shader2 GL_NV_texture_shader3 GL_NV_transform_feedback GL_NV_transform_feedback2 GL_NV_uniform_buffer_unified_memory GL_NV_uniform_buffer_std430_layout GL_NV_vertex_array_range GL_NV_vertex_array_range2 GL_NV_vertex_attrib_integer_64bit GL_NV_vertex_buffer_unified_memory GL_NV_vertex_program GL_NV_vertex_program1_1 GL_NV_vertex_program2 GL_NV_vertex_program2_option GL_NV_vertex_program3 GL_NV_viewport_array2 GL_NV_viewport_swizzle GL_NVX_conditional_render GL_NVX_linked_gpu_multicast GL_NV_gpu_multicast GL_NVX_gpu_multicast2 GL_NVX_progress_fence GL_NVX_gpu_memory_info GL_NVX_multigpu_info GL_NVX_nvenc_interop GL_NV_shader_thread_group GL_NV_shader_thread_shuffle GL_KHR_blend_equation_advanced GL_KHR_blend_equation_advanced_coherent GL_OVR_multiview GL_OVR_multiview2 GL_SGIS_generate_mipmap GL_SGIS_texture_lod GL_SGIX_depth_texture GL_SGIX_shadow GL_SUN_slice_accum GL_WIN_swap_hint WGL_EXT_swap_control 

Thanks Ged_Traynor. Can’t move it. I copied it to the Lightroom Classic forum.

This thread was posted in November 2025 and wasn’t migrated to the new forum until now.

I found a short notice in my archive and ​@Rikk Flohr_Photography wrote that he can reproduce this on Windows (and not on Macs) and logged this as a bug. 

As I wrote in my former answer I can’t reproduce this on my Windows machine. So it seems that this issue appears only on appropriate configurations. Such problems are very difficult to find.