Separate Preview and Viewer Tabs for Improved Multitab Workflow

[stx-chris]

Hi team,

I’ve been working with Positron for a few weeks now, primarily using it for Quarto projects — including a book, presentations, and data-heavy documents with embedded R code. Overall, the experience has been excellent. However, there is one key limitation that significantly impacts my workflow: the restriction to a single active preview instance in the Viewer and its non-distinction from completely rendered content.

🧩 The Problem

In practice, I often need to compare multiple Quarto documents side by side, especially to ensure consistency in layout, chart styles, or formatting between:
• a primary source document (e.g., main report with charts and data)
• a Quarto presentation referencing or reusing parts of that output
• different chapters of a book project

Currently, each time I generate a new preview for one file, any previous preview is discarded, even if that file is still open in another tab. This creates friction in workflows like:
1. Write and preview code (often R code generating charts) in the main document
2. Switch to the presentation document, preview layout and identify an issue
3. Return to the main document, adjust code, preview again
4. Return to the presentation, preview again
5. Repeat, often dozens of times per session

Each switch requires waiting for the document to re-render, and context is lost between previews, which slows down iteration and comparison.

💡 Suggested Improvement

I’d like to propose the introduction of a dedicated “Preview” tab distinct from the existing “Viewer”:
• The Viewer tab would continue to display fully rendered documents.
• A new Preview tab would show partial previews, tied to the currently active document tab.
• Switching between document tabs would automatically update the Preview tab with the last preview of that file (or prompt re-generation if necessary).
• This separation would prevent a preview of one file from overwriting the preview of another, which is especially useful in multi-document workflows.

This change would allow for non-destructive previews and make Positron significantly more productive for users managing interrelated Quarto files. I'd appreciate any feedback or suggestions from the community