Sub menu arrows are not visible when using a light theme

[dmtweigt]

Issue Type: Bug

1. Start VS Code
2. Go to File > Preferences > Color Theme
3. Pick a light theme
4. Open the File menu (or any other with sub menus)

Observed: Preferences and Open Recent menu items have invisible arrows, unless the mouse is hovered over them
Expected: Preferences and Open Recent menu items have arrows that are always visible

dark theme	light theme

VS Code version: Code - Insiders 1.31.0-insider (b313db6, 2019-02-05T10:16:27.989Z)
OS version: Windows_NT x64 6.1.7601

System Info

Item	Value
CPUs	Intel(R) Xeon(R) CPU E3-1241 v3 @ 3.50GHz (8 x 3500)
GPU Status	2d_canvas: enabled checker_imaging: disabled_off flash_3d: enabled flash_stage3d: enabled flash_stage3d_baseline: enabled gpu_compositing: enabled multiple_raster_threads: enabled_on native_gpu_memory_buffers: disabled_software rasterization: enabled surface_synchronization: enabled_on video_decode: enabled webgl: enabled webgl2: enabled
Memory (System)	15.93GB (7.96GB free)
Process Argv
Screen Reader	no
VM	0%

Extensions: none

[vscodebot]

(Experimental duplicate detection)
Thanks for submitting this issue. Please also check if it is already covered by an existing one, like:

• Sub menu not working when scrolling menus is enabled. (#65206)
• [themes] Add a "Recently Used" section at the top of the color themes menu (#54597)

[bpasero]

I can reproduce:

@sbatten @misolori didn't we change the arrow icons in this release to be smaller?

[sbatten]

@bpasero this actually reproduces in stable as well, but not in sources so still investigating

[sbatten]

got it. as a workaround, just reload the VS Code window after switching to the default light themes.

When the menu gets styled at launch, the styler picks either the theme's menu fg color or falls back to the default fg color. since the built-in dark theme has a menu fg color, this is what is set. Later when you switch to the light theme, there is no menu fg color so it gets set to null because menu fg defaults to null on light themes.