- Rollback all redundant changes made in the last few months
- Introduce `contextPane`
- Show child notes in the notes pane
- Fix splitter styling
- Various bug fixes
- Fix contextPane switching and states persistence
- Persist reader sidebar open/close state
- Fix bottom pane placeholder updating concurrency issues
- Fix toolbar placeholder width updating
- Display titles for split button
- Fix toolbar position when switching tabs
- Add PDF tab loading cover
- Improve notes and citations insertion
- Clean up and refactor code
- Fixes and cleanups to PDF reader
