Fix cursor positioning in notebook cells with horizontal scrolling

[Copilot]

Description

Mouse clicks in notebook code cells with long lines incorrectly placed the cursor at line end instead of the click position. Occurred when opening notebooks or re-rendering cells without saved view state.

Root cause: When attachTextEditor() detected horizontal scrolling but had no saved view state, it forced Monaco editor restoration with empty cursorState: [] and scrollLeft: 0, breaking coordinate mapping.

Fix: Remove forced view state restoration. Let Monaco initialize naturally.

// Before
if (this._editorViewStates) {
    this._restoreViewState(this._editorViewStates);
} else if (estimatedHasHorizontalScrolling) {
    this._restoreViewState({
        cursorState: [],              // Empty - breaks coordinate mapping
        viewState: { scrollLeft: 0, ... }
    });
}

// After
if (this._editorViewStates) {
    this._restoreViewState(this._editorViewStates);
}
// Natural initialization preserves coordinate mapping

Changes

• Remove lines 279-292 in baseCellViewModel.ts that force empty view state
• Preserve estimatedHasHorizontalScrolling parameter for API compatibility

Testing

Manual test with notebooks containing 200+ character lines:

1. Click mid-line → cursor at click position (not line end)
2. Reopen notebook → click positioning still correct
3. Scroll cell out of view and back → click positioning still correct

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Cursor always stick to the end of line in Notebooks</issue_title>
<issue_description>

Does this issue occur when all extensions are disabled?: Yes

I'm having a particular weird issue where I'm unable to select specific parts of a line inside a Jupyter notebook cell and instead my cursor is placed at the end of the lines, unless I modify it.

I attach a video describing the situation, note that I am clicking any point within the line but the cursor is always sticking to the rightmost side of it (for most lines). I cannot select a specific part of the lines and double clicking will select the whole line instead.

Recording.2024-10-20.025723.mp4

• VS Code Version: 1.94.2
• OS Version: Windows 11 NT 10.0; Win64; x64

Steps to Reproduce:

1. Have a Jupyter notebook opened, in my case I'm using it through WSL.
   I'm still not quite sure what causes it, because it often happens when reloading/opening the notebook from disk but sometimes it appears to be triggered when cells are unrendered from view.
2. Click on any recently unmodified line, the cursor should jump to the end

Console log doesn't show anything and/or maybe I haven't checked on every log.
From what I know, disabling extensions (except WSL) doesn't fix the issue and it can still be triggered when selecting a line in another cell.
</issue_description>

<agent_instructions>Have a look at the recording and comments, then perform root cause analysis before attempting to fix</agent_instructions>

Comments on the Issue (you are @copilot in this section)

@rebornix @JotaRata do you run into the same issue when using notebook from local workspace (non-WSL)?

• Fixes Cursor always stick to the end of line in Notebooks #231773

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