iMessage

• iMessage beta 1 will be unable to communicate with iMessage users on beta 2 or later.
• NEW:Setup Assistant does not input AppleID password in for FaceTime of iMessage.

interface Builder

• NEW:The top-level views in a document that uses autolayout cannot have width and height constraints added. To workaround this you can add desired width or height constraint manually in code.
• NEW:In Interface Builder documents using autolayout and constraints that Xcode generates cannot be deleted. You can “delete” these constraints by creating a user constraint for the behavior you are expecting. For example, if you drag out a button and Xcode generates a leading constraint to the button's superview, and you wanted a trailing edge to the superview constraint, creating one manually using “Add Constraint => Trailing Constraint to Superview” would remove the leading edge to superview constraint.
• NEW:It is known that equal widths/heights constraints can be broken on views that fill a container when resizing the window. If you resize the window and a equal widths/height constraint is broken, re-adding it will properly adjust the window to accommodate the constraint.
• NEW: When editing the value of a constraint in the inspector, the constraint remains selected, and the outline view continues to show the constraint as selected.
• NEW:In XCode 4.2 when copying views (either a single view or multiple views), both the user defined constraints directly on the selected view and the user defined constraints between the views being copied are copied to the pasteboard.
• NEW:In Xcode 4.2 for a document using Cocoa Auto Layout, “Select All” in the canvas no longer selects the constraints and subviews of the edited view. If a view is selected, it will only select views. If a constraint is selected, “Select All” will select all constraints.
• NEW:Changing the segment style of an NSSegmentedControl to “Automatic” might crash in documents using Cocoa Auto Layout. To workaround the issue use an explicit segment style such as Round or Textured, and at runtime, change the segment style to automatic using -[NSSegmentedCell setSegmentStyle:]

iPod

• FIXED: When using the volume buttons on the device, or on headphones, the volume slider in the UI of applications may not update even though the volume level has changed.