During August 2025, Adva-CG developed a character-by-character highlighting feature for partial word translation in the koreader/koreader repository. This enhancement introduced a move_by_char mode within the highlight dialog, allowing users to precisely select text segments by long-pressing edit controls. The implementation focused on frontend and UI development using Lua, emphasizing gesture-based controls and incremental feature delivery. By enabling finer granularity in text selection, Adva-CG improved translation accuracy and streamlined user workflow. The work demonstrated thoughtful UI/UX design and laid the foundation for advanced translation and accessibility features, with clear traceability through aligned pull requests and commit history.