the Undo functionality no longer works

Root cause

Press This uses BlockEditorProvider directly rather than the full EditorProvider from @wordpress/editor. BlockEditorKeyboardShortcuts (which is included) only registers block-level shortcuts like duplicate and remove — not undo/redo. In the full Gutenberg editor, EditorKeyboardShortcuts registers Ctrl+Z / Cmd+Z, but Press This never included it.

Before paste, the browser's native contentEditable undo stack handles Ctrl+Z for typing. When the user pastes, Gutenberg intercepts the event and processes clipboard data programmatically (creating/replacing blocks through React and the store), which invalidates the native undo stack. After that, Ctrl+Z has nothing to undo natively, and no keyboard shortcut is wired to the block editor store's undo() action.