Markdown preview scrolls down while typing in editor

[magiblot]

Issue Type: Bug

1. Open the following document: https://github.com/magiblot/tvision/blob/28246145506f4397c4358fcacd6c2f4d9c89ff8f/README.md

2. Enable the document preview.

3. Do any of the following:

   • Type text near the end of the document, e.g. line 708.
   • Scroll the preview near the end of the document. Then go to Settings, search "Markdown" and keep toggling "Markdown > Preview: Scroll Editor With Preview" or "Markdown > Preview: Scroll Preview With Editor".

   The preview will scroll up on each update, and so will the editor until the cursor is about to become out of sight.

To make the issue more evident, set markdown.preview.scrollEditorWithPreview to false.

The issue is reproducible even after disabling extensions with the workbench.action.reloadWindowWithExtensionsDisabled command.

VS Code version: Code 1.54.3 (2b9aebd, 2021-03-15T10:55:24.277Z)
OS version: Linux x64 5.11.7-arch1-1

System Info

Item	Value
CPUs	Intel(R) Core(TM) i5-6200U CPU @ 2.30GHz (4 x 2400)
GPU Status	2d_canvas: enabled gpu_compositing: enabled multiple_raster_threads: enabled_on oop_rasterization: disabled_off opengl: enabled_on protected_video_decode: enabled rasterization: disabled_software skia_renderer: enabled_on video_decode: disabled_software vulkan: disabled_off webgl: enabled webgl2: enabled
Load (avg)	1, 1, 1
Memory (System)	11.63GB (4.63GB free)
Process Argv	--no-sandbox --unity-launch --ignore-gpu-blacklist --crash-reporter-id 2993da31-a167-44bc-bba0-3373266d8467
Screen Reader	no
VM	0%
DESKTOP_SESSION	undefined
XDG_CURRENT_DESKTOP	KDE
XDG_SESSION_DESKTOP	undefined
XDG_SESSION_TYPE	tty

Extensions: none

A/B Experiments

vsliv368:30146709
vsreu685:30147344
python383:30185418
vspor879:30202332
vspor708:30202333
vspor363:30204092
vstry914:30276682
pythonvsdeb440:30248342
pythonvsded773:30248341
pythonvspyt875:30259475
pythontbcf:30265426
vscoresta800cf:30276762
vspre833cf:30267465
vsfjg287:30275553
vshan820cf:30276953

[vscodebot]

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

• Help test and implement the markdown custom editor preview (#84520)
• markdown files preview does not save scroll position (#63690)
• Markdown Preview keyboard shortcut doesn't work for editor in Preview Mode (#115458)
• Drag markdown preview to New Window (#32818)
• Web: Markdown Preview scrolling not synced on iPadOS (#83714)

[magiblot]

Screen recording of the issue:

simplescreenrecorder-2021-03-20_00.26.52.2.mp4

[NeoFantom]

Almost same problem here. I however found that, this problem is most abvious when you have a big math expression, for example if you cantain this math code in md:

(some very very long text, more than one page)

$\displaystyle \mathrm{softmax}(\mathbf{x}) =
\begin{pmatrix}
\frac{e^{x_1}}{\sum_j e^{x_j}} \\
\vdots \\
\frac{e^{x_n}}{\sum_j e^{x_j}}
\end{pmatrix}$

**then type something here**

(some other very very long text)

Then type in middle, you'll find it scrolling down very fast every time it refreshes.

[willstocks]

Adding images seems to make this issue even worse as well... I also find mine both scrolling down, but then also the preview jumping way back up and then back down!

In this GIF, the Preview is jumping all the way back up to around line 600 (so about 1/5 - 1/4 of the way back up the document). I've tried to highlight the scrolling issue (jumping on the actual file on the left) as well as the weird preview scrolling behaviour.

Persists with extensions disabled or not.

Windows 10 Enterprise 21H1 (19043.1055), VS Code 1.57.1

[ticapix]

I have the same issue with 1.59.1 and mermaid diagrams.

Here is a sample content https://pastebin.com/eN0aWK4Q to reproduce issue when editing line 12 for example.

[isidorn]

I also see this all the time, especially when using github.dev. @mjbvz can you reproduce this? Do you also see this when using github.dev, ruins my whole editing release notes experience.

[mjbvz]

Duplicate of #89930