use the formLayout command to set up a window

Hello everyone! I try to use the formLayout command to create a
window.But once
I use the flag "-attachOppositeControl" in the script ,my maya will
close itself quickly,how can you tell me why?
TIA! the following is the script.
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if (`window -exists hardWidowUI`)
deleteUI hardWindowUI;
//create the window
window -t "Simplify the Channel Box for Animator"
	   -mxb off
	   -sizeable on
	   hardWindowUI;
//set the main column layut
columnLayout mainCol;
//the first frame layout
frameLayout -l "Lock<--------------------->Unlock"
			-collapsable off
			-collapse off
			-borderStyle "etchedIn"
			firstFL;
formLayout form1;
button -l "Translate" but1;
button -l "Translate" but2;
button -l "Rotate" but3;
button -l "Rotate" but4;
button -l "Scale" but5;
button -l "Scale" but6;
formLayout -edit
		-attachForm but1 "left" 6
		-attachForm but1 "top" 10
		-attachControl but1 "right" 4 but2

		-attachForm but2 "right" 6
		-attachForm but2 "top" 10
		-attachOppositeControl but2 "bottom" 0 but1

		-attachForm but3 "left" 6
		-attachControl but3 "top" 4 but1
		-attachControl but3 "right" 4 but4

		-attachForm but4 "right" 6
		-attachControl but4 "top" 4 but2
		-attachOppositeControl but4 "bottom" 0 but3

		-attachForm but5 "left" 6
		-attachControl but5 "top" 4 but3
		-attachControl but5 "right" 4 but6

		-attachForm but6 "right" 6
		-attachControl but6 "top" 4 but4
		-attachOppositeControl but6 "bottom" 0 but5
form1;
showWindow hardWindowUI;