During March 2025, HisMove2021 focused on stabilizing nested data operations in the handsontable/handsontable repository by addressing a critical issue in the NestedRows plugin. He resolved a bug that caused child rows to duplicate when moved, thereby improving data integrity and reliability for users manipulating nested structures. His approach involved targeted adjustments in JavaScript, specifically refining dataManager.js to accurately identify parent row indices during synchronization. He also developed comprehensive tests for dragRow and dragRows functionalities, ensuring future regressions are prevented. His work demonstrated depth in plugin development and testing, resulting in more robust nested row handling within the codebase.