Marks the beginning of an undo group.
- iOS 3.0+
- macOS 10.0+
- Mac Catalyst 13.0+
- tvOS 9.0+
- watchOS 2.0+
All individual undo operations before a subsequent
endUndoGrouping() message are grouped together and reversed by a later
undo() message. By default undo groups are begun automatically at the start of the event loop, but you can begin your own undo groups with this method, and nest them within other groups.
This method posts an
NSUndoManagerCheckpoint unless a top-level undo is in progress. It posts an
NSUndoManagerDidOpenUndoGroup if a new group was successfully created.
Creating Undo Groups
var groupsByEvent: Bool
A Boolean value that indicates whether the receiver automatically creates undo groups around each pass of the run loop.
var groupingLevel: Int
The number of nested undo groups (or redo groups, if Redo was invoked last) in the current event loop.