Markdown Preview does not preserve scroll position

[danieljl]

• VSCode Version: 1.10.2
• OS Version: Ubuntu 14.04

Steps to Reproduce:

1. Open a Markdown file.
2. Open the preview (ctrl+shift+v).
3. Close the Markdown file tab (not the preview).
4. Scroll a few times in the preview tab.
5. Open any other file.
6. Go to the preview tab again. Notice that the scrollbar is reset to top.

My suggestion is that the scroll position of Markdown preview tab should follow its corresponding raw Markdown tab's only if the raw Markdown tab is present. If it is not present, the preview tab should preserve the last scroll position.

[slfuqua]

• VSCode Version: 1.11.1
• OS Version: Ubuntu 14.04

Steps to Reproduce:

1. Open a Markdown file, place cursor anywhere in file other than the top
2. Open the Preview (ctrl+shift+v).

More generally than above, the "Preview" tool now (unlike previously) always resets to the top of the markdown file when you open it or go to its tab and it refreshes (or you press ctrl+shift+v). It no longer goes to the current edit (cursor) location in the raw file. It is inconvenient to repeatedly scroll down to the current edit location in long files, to preview the changes.

I'm pretty sure I skipped a couple of version updates until I installed 1.11.1 today (4/9/2017), so I'm not sure when the behavior changed, but it was fairly recent, my version was not too outdated, no more than two or three updates.

[jdim]

Same behavior

• VSCode Version: 1.12.0-insider
• OS Version: Ubuntu 16.04

[rebornix]

Re #22279, run into this issue while following the guidance of the project.

[mjbvz]

@rebornix Can we try debugging through the issue on your machine this afternoon?

[chaskim]

I have the same problem as outlined by @slfuqua.

• VS Code 1.11.2
• macOS 10.11.6

It worked okay in earlier versions of VS Code (I believe it worked okay in 1.10.x).

[mjbvz]

For anyone seeing this problem, #24985 just added some basic logging to help investigate. The change be in the next insiders build. Once that is released, please download it and:

• Set "markdown.trace": "verbose"
• Reproduce the issue
• Go to the output pane and share the output from the Markdown section

This should help me investigate what may be going wrong here

[chaskim]

@mjbvz Thanks very much for looking into this. Below is my output after setting markdown.trace to verbose in VS Code 1.12.0-insider. The first entry is when I click somewhere in the middle of the markdown document. The second is when I use the preview option (which still shows the very top of the document instead of where my cursor was in the actual markdown document).

[Log - 11:43:07 AM] updatePreviewForSelection
{
  "markdownFile": "markdown:/Users/Charles/Develop/Personnel/BlocNotes/aurelia-snippets.md.rendered?file%3A%2F%2F%2FUsers%2FCharles%2FDevelop%2FPersonnel%2FBlocNotes%2Faurelia-snippets.md"
}
[Log - 11:43:10 AM] provideTextDocumentContent
{
  "previewUri": "markdown:/Users/Charles/Develop/Personnel/BlocNotes/aurelia-snippets.md.rendered?file%3A%2F%2F%2FUsers%2FCharles%2FDevelop%2FPersonnel%2FBlocNotes%2Faurelia-snippets.md",
  "source": "file:///Users/Charles/Develop/Personnel/BlocNotes/aurelia-snippets.md",
  "line": 0,
  "scrollPreviewWithEditorSelection": true,
  "scrollEditorWithPreview": true,
  "doubleClickToSwitchToEditor": true
}

I see that the "line" entry is zero. Maybe the issue is related to that?

[mjbvz]

Thanks @chaskim!

From your log, I think there's a bug in the markdown preview where using Open Preview instead of Open Preview to Side causes the initial line not to be set. Looking into a fix

[isidorn]

Potentially dup of #22420