# Changelog All notable code changes to **Markdown Viewer** are documented here. Non-code commits (documentation, planning, README-only updates) are excluded. ## v3.7.4 - **Description:** Delivered substantial feature additions and reliability improvements, including language expansion, desktop app startup fix, export centering, re-engineered PDF page breaking, and advanced Find & Replace features. - **Internationalization (i18n):** Added 9 new UI languages and synchronized desktop resources to improve global accessibility. - **Desktop App Startup:** Fixed Windows desktop app startup issues for improved launch reliability. - **HTML Export Centering:** Added support for script-disabled alignment centering for HTML exports (fixes #152). - **Re-engineered PDF Page Breaks & Scaling:** Resolved text slicing, table pagination, layout overlaps, blockquote/callout pagination splits, and margin-collapse layout shifting. Serialized rendered Mermaid diagrams to base64 images for physical scaling and gap-less page breaks (fixes #166). - **TOC Smooth Scrolling:** Resolved smooth scroll navigation for Table of Contents anchor links and prevented hash/address bar updates (fixes #169). - **Find & Replace Pane Synchronization:** Implemented match highlighting and auto-scrolling to matches in the Preview Pane, and fixed alignment of editor pane highlights (fixes #169). - **Date:** 2026-06-10 - **URL:** https://github.com/ThisIs-Developer/Markdown-Viewer/commit/8ea71a809063effe849b418da5e4b4527102a10f --- ## v3.7.3 - **Description:** Delivered critical rendering, export, and editor reliability fixes across the application. - **Large Document Performance:** Re-engineered the preview rendering pipeline for large documents, improving editor responsiveness and fixing preview rendering failures on large files. - **PDF Export Improvements:** Improved PDF generation UX with better progress feedback, fixed exported document centering, and resolved Mermaid diagram rendering failures in PDF export. - **Find & Replace Scrolling:** Fixed find match scrolling so navigating between search results correctly scrolls the matched text into view. - **Toolbar Markdown Preservation:** Fixed toolbar formatting actions to preserve existing markdown content instead of overwriting it. - **Date:** 2026-06-05 - **URL:** https://github.com/ThisIs-Developer/Markdown-Viewer/commit/a6d062d9696d958904f493d82d8bc2299522f5e2 --- ## v3.7.2 - **Description:** Implemented custom editor history, a new clear document action, tab layout enhancements, and visual optimizations for theme switching. - **Editor Undo/Redo & Actions:** Implemented custom, robust in-memory document editing history state trackers (Undo/Redo stack) and added a dedicated "Clear Document" toolbar button. - **Tabs Layout & Overflow:** Relocated the "New Tab" button and engineered dynamic container overflow handling to prevent navigation toolbar wrap. - **Mermaid.js Theme Change Synchronization:** Deferred diagram re-rendering and added synchronized fade transitions during theme changes to prevent structural canvas errors, while preserving instant color switches. - **Accessibility & CSS Refactoring:** Removed redundant mobile layout direction buttons; enabled window scroll on mobile viewports for menu access; and cleaned up outer layout scrollbars. - **Date:** 2026-06-03 - **URL:** https://github.com/ThisIs-Developer/Markdown-Viewer/commit/4a9cc6a0b602a377a1e30e64205fff7733472ed8 --- ## v3.7.1 - **Description:** Scoped performance optimizations, accessibility remediation, onboarding template stabilization, and library upgrades. - **Performance & Reflows:** Scoped in-memory caching to editor geometry and gutter layouts to eliminate forced synchronous reflows; debounced resize layout listeners and deferred non-critical startup initializations to accelerate page load and cut Total Blocking Time (TBT). - **Accessibility (a11y):** Resolved multiple Lighthouse accessibility violations; fixed line-number contrast ratios for both light and dark themes; increased touch target sizes conforming to WCAG AA guidelines. - **Onboarding & Templating:** Stabilized the onboarding template initialization (resolving `BUG-ONBOARD-001`); inlined the default welcome markdown; and migrated it to a `