Worked on enhancing document stability and data integrity in the FreeCAD/FreeCAD repository, focusing on multi-document workflows. Addressed a critical issue where empty startup documents would disappear when switching between documents by introducing an autoCreated flag to differentiate between auto-created and manually created documents. Updated the document-switch lifecycle so that only auto-created empty documents are closed, ensuring user-created content is preserved and reducing the risk of data loss. Utilized C++ and Python for bug fixing, software development, and testing. These changes improved the reliability of document handling, providing a more consistent and trustworthy editing experience for FreeCAD users.