Title bar color is broken and Quick Pick flashes when workbench.experimental.modernUI is enabled on Windows

[SkeadyZi]

Type: Bug

System Information

• VS Code Version: 1.131.x (Latest Stable)
• OS: Windows 11 23H2 (Also confirmed on Ubuntu 24.04)
• CPU Architecture: x64

Steps to Reproduce

1. Open VS Code Settings (Ctrl + ,).
2. Search for modernUI and check the box to enable Workbench › Experimental: Modern UI.
3. Set the active color theme to Quiet Light.
4. Observe the Title Bar at the top of the window.
5. Click the Gear icon (⚙) -> Color Theme to open the Quick Pick menu.

Actual Behavior

• Title Bar Rendering: When Modern UI is enabled with the Quiet Light theme, the title bar loses its expected purple color (#c4b7d7). Instead, the left side of the title bar turns white/gray, while only the window control buttons (minimize, maximize, close) on the far right retain the purple color. This creates a visually inconsistent split appearance.
• Quick Pick Instability: After enabling Modern UI, clicking the Gear icon to change the theme sometimes causes the Quick Pick panel to flash (open and immediately close), making it impossible to select a theme without multiple attempts.

Expected Behavior

• Title Bar: The entire title bar, including the area to the left of the window controls, should render with the consistent color defined by the Quiet Light theme.
• Quick Pick: The Quick Pick menu should remain stable and open reliably when triggered via the Gear icon.

Workaround

This issue can be completely resolved by explicitly disabling the experimental feature in settings.json:

VS Code version: Code 1.131.0 (e4c7e7b, 2026-07-28T10:51:25Z)
OS version: Windows_NT x64 10.0.26200
Modes:

System Info

Item	Value
CPUs	11th Gen Intel(R) Core(TM) i5-1135G7 @ 2.40GHz (8 x 2419)
GPU Status	2d_canvas: enabled GPU0: VENDOR= 0x8086, DEVICE=0x9a49 [Intel(R) Iris(R) Xe Graphics], DRIVER_VENDOR=Intel, DRIVER_VERSION=31.0.101.4255 ACTIVE GPU1: VENDOR= 0x1414, DEVICE=0x008c [Microsoft Basic Render Driver], DRIVER_VERSION=10.0.26100.8875 Machine model name: Machine model version: direct_rendering_display_compositor: disabled_off_ok gpu_compositing: enabled multiple_raster_threads: enabled_on opengl: enabled_on rasterization: enabled raw_draw: disabled_off_ok skia_graphite: disabled_off trees_in_viz: disabled_off video_decode: enabled video_encode: enabled webgl: enabled webgpu: enabled webnn: disabled_off
Load (avg)	undefined
Memory (System)	15.70GB (8.87GB free)
Process Argv	--crash-reporter-id 90486901-23ca-45ab-8e8f-7ab75402de95
Screen Reader	no
VM	0%

Extensions (5)

Name	Identifier	Author	Version
CMake Tools	ms-vscode.cmake-tools	ms-vscode	1.23.52
C/C++ DevTools	ms-vscode.cpp-devtools	ms-vscode	0.5.13
C/C++	ms-vscode.cpptools	ms-vscode	1.32.2
C/C++ Extension Pack	ms-vscode.cpptools-extension-pack	ms-vscode	1.5.1
Makefile Tools	ms-vscode.makefile-tools	ms-vscode	0.12.17

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