Submenu at wrong position when sider bar is at right side

[yume-chan]

Issue Type: Bug

Testing #100848

If the side bar is at right side, the Extensions -> View submenu appears at wrong position.

VS Code version: Code - Insiders 1.47.0-insider (0913b1a, 2020-06-23T09:03:35.861Z)
OS version: Windows_NT x64 10.0.18363

System Info

Item	Value
CPUs	Intel(R) Core(TM) i7-1065G7 CPU @ 1.30GHz (8 x 1498)
GPU Status	2d_canvas: enabled flash_3d: enabled flash_stage3d: enabled flash_stage3d_baseline: enabled gpu_compositing: enabled multiple_raster_threads: enabled_on oop_rasterization: disabled_off opengl: enabled_on protected_video_decode: enabled rasterization: enabled skia_renderer: disabled_off_ok video_decode: enabled viz_display_compositor: enabled_on webgl: enabled webgl2: enabled
Load (avg)	undefined
Memory (System)	15.60GB (5.66GB free)
Process Argv
Screen Reader	no
VM	0%

Extensions (22)

Extension	Author (truncated)	Version
Bookmarks	ale	11.3.1
vscode-eslint	dba	2.1.5
gitlens	eam	10.2.2
flow-for-vscode	flo	1.5.0
rest-client	hum	0.24.1
search-node-modules	jas	1.3.0
tabsanity	jed	0.0.11
vscode-language-pack-zh-hans	MS-	1.46.3
remote-ssh	ms-	0.51.0
remote-ssh-edit	ms-	0.51.0
remote-wsl	ms-	0.44.4
hexeditor	ms-	1.0.1
powershell-preview	ms-	2020.6.1
typescript-javascript-grammar	ms-	0.0.53
vscode-js-profile-table	ms-	0.0.5
vscode-typescript-next	ms-	4.0.20200622
vsonline	ms-	1.0.2390
vscode-jest	Ort	3.2.0
vscode-autohide	sir	1.0.5
code-spell-checker	str	1.9.0
vscode-icons	vsc	10.1.1
material-theme	zhu	3.8.2

[sbatten]

The menu is using the menubar logic and is unaware that it should flow left. Need to either adopt a flow direction in the toggle more button or make the menu logic more advanced.

[yume-chan]

@sbatten If I set "window.menuBarVisibility": "compact", and with my side bar on the right side, submenus will correctly flow to the left. I don't know if it's hard coded or it's smart enough to know there is no room at right side.

[sbatten]

Compact menubar has the logic that this needs to adopt

[yume-chan]

Now the missing of background makes it totally unusable.

Version: 1.48.0-insider (user setup)
Commit: 731f9c25632dbbf01ee3a7892ad9d2791fe0260c
Date: 2020-07-24T05:57:10.466Z
Electron: 9.1.0
Chrome: 83.0.4103.122
Node.js: 12.14.1
V8: 8.3.110.13-electron.0
OS: Windows_NT x64 10.0.19041

[qcz]

The problem is much worse when trying to use the new proposed submenus API in a right side sidebar editor context menu: