My Stack frame appears to be different than shown on page 152 starting at #3. My breakpoint is set at the first line after the first opening curly bracket in the setter code and my code seems to execute correctly as described in the text. Xcode version 6.3.2
#0 Thermostat.MainWindowController.temp.setter : Swift.Int
#1 @objc Thermostat.MainWindowController.temp.setter : Swift.Int ()
#2 _NSSetLongLongValueAndNotify ()
#3 Thermostat.MainWindowController.makeCooler (Thermostat.MainWindowController)(ObjectiveC.NSButton) -> ()
#4 @objc Thermostat.MainWindowController.makeCooler (Thermostat.MainWindowController)(ObjectiveC.NSButton) -> () ()
#5 _os_activity_initiate ()
#6 -[NSApplication sendAction:to:from:] ()
#7 -[NSControl sendAction:to:] ()
#8 __26-[NSCell _sendActionFrom:]_block_invoke ()
#9 _os_activity_initiate ()
#10 -[NSCell _sendActionFrom:] ()
#11 in _os_activity_initiate ()