Markdown preview jumps a bit on every keystroke

[alexdima]

Issue Type: Bug

• have a markdown preview to the side
• type in the .md file
• the preview jumps a bit on each keystroke

VS Code version: Code - Insiders 1.42.0-insider (be0aca7, 2020-01-31T14:45:49.503Z)
OS version: Windows_NT ia32 10.0.18362

[mjbvz]

This is related to how the markdown is syncing the scroll. Some points of interest:

1. This code runs in the markdown preview (which is a webview):

   vscode/extensions/markdown-language-features/preview-src/scroll-sync.ts

   Line 1 in b103356

   /*---------------------------------------------------------------------------------------------

2. Look at where function such as scrollToRevealSourceLine are being called from

To build the markdown preview (after changing any file under preview-src):

1. cd extensions/typescript-language-featutes
2. yarn run build-preview

[meganrogge]

@mjbvz There isn't a script called build-preview in the extensions/typescript-language-features package.json.

Also, I can't re-produce this issue.

[mjbvz]

Should be fixed by 8f672ca

There are likely still a few edge cases where it won't work perfectly, but the original example and other tests in vscode-docs worked for me