drive_value_takes_the_keyboard and boundary_fill_finds_the_cells_and_fills_the_ticked_ones dropped egui's output with texture deltas still pending (epaint's debug check); they clear them as the scenario harness does. All ui-egui tests pass in a debug build. Fixes #60 Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01RjGw4gA5ZvKrU8MQP6sBgT