Worked on improving the stability of window management in the reactos/reactos repository by addressing a bug related to parent window handling during user-mode callbacks. Focused on C programming and Windows API, the solution involved caching the parent window object locally before sending messages, ensuring that dereferencing operations remained consistent even if the parent changed mid-callback. This approach prevented assertion failures and reduced the risk of crashes when parent windows were modified during callback flows. The work demonstrated a strong understanding of system programming concepts and contributed to more reliable GUI behavior, directly resolving issues linked to parent reference mismatches.