Unstable Markdown Editing Windows

[diophant0x]

Issue Type: Bug

Create a markdown file and open up the preview and move it to a tab on the side so that both raw and rendered Markdown are visible. Create any content up to 50 lines long, each line separated by newline separators. Now as you type you will notice both windows shaking and scrolling upwards as you type. This is very annoying and both windows should remain in place unless I scroll manually.

VS Code version: Code 1.60.2 (7f6ab54, 2021-09-22T11:59:27.195Z)
OS version: Darwin x64 20.5.0
Restricted Mode: No

System Info

Item	Value
CPUs	Intel(R) Core(TM) i9-9880H CPU @ 2.30GHz (16 x 2300)
GPU Status	2d_canvas: enabled gpu_compositing: enabled metal: disabled_off multiple_raster_threads: enabled_on oop_rasterization: enabled opengl: enabled_on rasterization: enabled skia_renderer: disabled_off_ok video_decode: enabled webgl: enabled webgl2: enabled
Load (avg)	2, 2, 2
Memory (System)	16.00GB (0.09GB free)
Process Argv	--crash-reporter-id f4b45347-26c9-4497-aa25-89472a2f90ba
Screen Reader	no
VM	0%

Extensions (4)

Extension	Author (truncated)	Version
python	ms-	2021.10.1317843341
vscode-pylance	ms-	2021.10.0
jupyter	ms-	2021.8.2041215044
jupyter-keymap	ms-	1.0.0

A/B Experiments

vsliv368cf:30146710
vsreu685:30147344
python383:30185418
pythonvspyt602:30300191
vspor879:30202332
vspor708:30202333
vspor363:30204092
vswsl492:30256859
pythonvspyt639:30300192
pythontb:30283811
pythonvspyt551:30345470
pythonptprofiler:30281270
vshan820:30294714
vstes263:30335439
pythondataviewer:30285071
pythonvsuse255:30340121
vscod805:30301674
pythonvspyt200:30340761
binariesv615:30325510
vsccppwt:30364497
pythonvssor306:30344512
bridge0708:30335490
pygetstartedt2:30371810
dockerwalkthru:30370836
bridge0723:30353136
pythonrunftest32:30373476
pythonf5test824:30373475
javagetstartedt:30364666
pythonvspyt187:30373474
pydsgsc2:30361791
vsqsis400:30374798

[gjsjohnmurray]

Maybe #133376

Are you able to test with the latest Insiders build?