Edit history and undo
⌘Z undoes, ⌘⇧Z redoes, and the history lets you jump several steps back.
Undo covers everything: adding, deleting, moving, editing text, styles, actions and conditions. Use the arrow buttons at the top or ⌘Z and ⌘⇧Z.

Data edits are undone too: a table added or removed, its columns and rows, the table name, entries in the app memory. Typing in one field is undone in one step, not letter by letter.
Edit history (⌘⇧H) is a list of steps in plain words: “Added: Button”, “Style changed”, “Wrapped in a container”. Click a step to return to that moment — faster than pressing undo twenty times.