Undo, Redo, and Dirty State

Filmstrip 0.5 adds a shared command foundation for reversible authoring work. A command records one meaningful change, while a grouped transaction combines several related edits into one undo step.

History behavior

• Ctrl+Z undoes the most recent applicable authoring command.
• Ctrl+Y redoes an undone command.
• Successful new work after an undo clears the redo branch.
• Failed commands roll back their partial work and do not enter history.
• Failed grouped operations roll back already-applied child changes and create no history entry.
• History is bounded so long sessions do not grow without limit.

Save checkpoints

Dirty state is based on revision identity rather than a simple one-way flag. Saving marks the current revision as the checkpoint. Undoing back to that exact revision becomes clean; moving away from it becomes dirty again.

Persistent editors

RPG Database and Dialogue changes are persisted atomically. Undo and redo write the restored validated snapshot immediately, so their status does not claim unsaved data is pending after the restored snapshot has already been written.

Tile history

Tile painting retains its established bounded stroke history and shares the same Ctrl+Z and Ctrl+Y routing. Filmstrip does not guess an unsafe ordering between unrelated history authorities.