In jupyter notebook, pressing Alt to make multi-cursor ends up focusing top-left-menu

[Guest-01]

Issue Type: Bug

if you open .ipynb file and alt click a code to make multi-cursor, the moment you release alt button the focus goes to top left window "File" menu. This doesn't happen on .py file. Is this a bug? I want to edit multiple lines in notebook but I can't.

Oh, and one more, if you alt-tab and come back, the focus also disappear. I do a lot of alt-tabing in order to reference API manuals but every then, I loose my keyboard focus which makes me annoying. I think this also has to do with pressing alt button.

VS Code version: Code 1.57.1 (507ce72a4466fbb27b715c3722558bb15afa9f48, 2021-06-17T13:28:07.755Z)
OS version: Windows_NT x64 10.0.19041
Restricted Mode: No

System Info

Item	Value
CPUs	Intel(R) Core(TM) i5-9600K CPU @ 3.70GHz (6 x 3696)
GPU Status	2d_canvas: enabled gpu_compositing: enabled multiple_raster_threads: enabled_on oop_rasterization: enabled opengl: enabled_on rasterization: enabled skia_renderer: enabled_on video_decode: enabled vulkan: disabled_off webgl: enabled webgl2: enabled
Load (avg)	undefined
Memory (System)	15.82GB (10.67GB free)
Process Argv	--crash-reporter-id 78b231af-0076-4dee-a915-c7b7b8678055
Screen Reader	no
VM	0%

Extensions (3)

Extension	Author (truncated)	Version
python	ms-	2021.6.944021595
vscode-pylance	ms-	2021.6.2
jupyter	ms-	2021.6.999406279

A/B Experiments

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pythonvspyt602:30300191
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vscextlangct:30322307
binariesv615:30323119

[rebornix]

This will be solved once the Jupyter extension dropped the custom editor impl.

[greazer]

Thanks for your feedback. This issue will be addressed once VS Code adds native support for editing notebooks. Please see microsoft/vscode#91987. You can experiment by using VS Code insiders, which defaults to the new notebook experience.