Worked on enhancing the reliability of JetBrains/Avalonia by addressing a complex issue with right-to-left (RTL) text handling in multi-line textboxes. Focused on correcting the traversal logic for text runs, the solution ensured accurate selection behavior for RTL languages across multiple lines. This involved reversing the text run traversal and introducing comprehensive unit tests to cover newline scenarios within RTL text, thereby strengthening the robustness of language support. The work was implemented in C# and emphasized text formatting and unit testing, prioritizing stability and maintainability over new feature development during the period, with all changes consolidated in a single commit.