UI Script to click the "detect displays" button in System Preferences on OS X 10.11 El Capitan

detect_displays.applescript

-- Minimally modified from:
-- http://www.insanelymac.com/forum/topic/59163-detect-displays-by-command-or-script/?p=457644
activate application "System Preferences"
tell application "System Events"
	tell application process "System Preferences"
		tell window 1
			click button "Show All" of group 1 of group 2 of toolbar 1 (* in case another pane is already open *)
			tell button "Displays" of scroll area 1
				repeat until exists (* wait until the object is accessible *)
					delay 0.2
				end repeat
				click
			end tell
			
			tell button "Detect Displays"
				repeat until exists (* wait until the object is accessible *)
					key down option
					delay 0.2
				end repeat
				click
				key up option
			end tell
		end tell
	end tell
end tell
tell application "System Preferences" to quit