Possible bug with the split terminal feature

[Titanium-ctrl]

Issue Type: Bug

When I open any 2 terminals in split mode, the terminal on the right loads up very unsually. The terminal text isn't laid out correctly and the cursor is way too far back, although the typing is normal. I think the problem is that the terminal on the right doesn't make a new line correctly. When running commands like ls in the terminal, I can see that the command runs normally, but the output is very messy.

Here is an image of what 2 Powershell terminals look like in split mode.

To reproduce this problem:

1. Open VS Code
2. Open a terminal
3. Add a second terminal in split mode

A basic fix for this is to add a 3rd terminal in split mode and then close it afterwards.

VS Code version: Code 1.56.0 (cfa2e21, 2021-05-04T22:09:06.405Z)
OS version: Windows_NT x64 10.0.19042

System Info

Item	Value
CPUs	Intel(R) Core(TM) i5-1035G1 CPU @ 1.00GHz (8 x 1190)
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)	7.79GB (1.15GB free)
Process Argv	--crash-reporter-id 95e332bb-1b35-4eb8-9fdf-2b3bbbae50a7
Screen Reader	no
VM	0%

Extensions (19)

Extension	Author (truncated)	Version
vscode-mysql-client2	cwe	3.7.2
vscode-eslint	dba	2.1.20
go	gol	0.24.2
vscode-docker	ms-	1.12.1
python	ms-	2021.4.765268190
jupyter	ms-	2021.6.811652604
remote-containers	ms-	0.177.0
remote-ssh	ms-	0.65.4
remote-ssh-edit	ms-	0.65.4
remote-wsl	ms-	0.56.1
vscode-remote-extensionpack	ms-	0.20.0
debugger-for-edge	msj	1.0.15
java	red	0.79.1
vscodeintellicode	Vis	1.2.13
vscode-java-debug	vsc	0.33.1
vscode-java-dependency	vsc	0.18.3
vscode-java-pack	vsc	0.14.0
vscode-java-test	vsc	0.29.0
vscode-maven	vsc	0.30.1

A/B Experiments

vsliv368:30146709
vsreu685:30147344
python383:30185418
pythonvspyt678:30270856
pythonvspyt602cf:30294773
vspor879:30202332
vspor708:30202333
vspor363:30204092
pythonvsnew554cf:30291488
pythontb:30283811
vspre833:30267464
pythonptprofiler:30281270
vsdfh931:30280409
vshan820:30294714
pythondataviewer:30285071
vscus158:30286553

[meganrogge]

/duplicate #73879

[Titanium-ctrl]

This is not a duplicate to #73879.
In short that issue is "Please don't default to an unsupported proportional font in the terminal just because the editor is using a proportional font" and this issue is "Please don't change the font of the second terminal when opening 2 terminals in split and then have it fix when a 3rd terminal is open"
In my opinion it seems like a bug but I don't know for sure.