During their work on the FreeCAD/FreeCAD repository, C. Nihelton focused on stabilizing the Start view tab handling within the application’s GUI. They addressed a bug where closing the Start view tab would inadvertently exit the entire application, implementing a solution in C++ that safely traverses the parent widget tree to ensure only the targeted QMdiSubWindow is closed. Their approach involved code refactoring and careful widget manipulation, including updating helper calls to remove constness for better alignment with the GUI lifecycle. The changes were isolated to the Start view, maintaining stability and preventing regressions in other modules throughout the codebase.