Fill row lays a full-width bar in the current graphics colour with one click. Box drags a bordered panel — hold Shift on release for a solid one. Select drags a region: Ctrl+C / X / V to copy, cut, and paste at the cursor, Delete clears, Escape drops the selection. Everything is undoable with Ctrl+Z.
Stages still drive the PNG sequence: number the cells, hit Stage rows ↓ for an automatic build-up, and Download all stages gives you one numbered frame per step. Flashing cells now actually blink in the editor.
The whole session — all eight pages, every setting in every tab — autosaves in this browser and lives in one project file via Save all up top.