Is this a bug?

I have one question though, using banks how come you cannot use banks for text areas? My code is below

window=CreateWindow("ABACUS",200,200,500,400,window,15)
menu=WindowMenu(window)
help=CreateMenu("Help",0,menu)
CreateMenu("About",1,help)
;Functions 
;This function has a window parameter because of the bank
Function SetUp(window)
	bank=CreateBank(35)
	PokeInt bank,5,CreateButton("+",100,300,75,75,window)
	PokeInt bank,10,CreateButton("-",200,300,75,75,window)
	PokeInt bank,15,CreateButton("*",300,300,75,75,window)
	PokeInt bank,20,CreateButton("/",400,300,75,75,window)
	PokeInt bank,25,CreateTextArea(100,100,50,50,window)
	PokeInt bank,30,CreateTextArea(400,100,50.50,window)
	;So we can use this bank everywhere else
	Return bank
End Function 
;This function will allow us to add,subtract,multiply and divide.
Function Math()
	plus=PeekInt(bank,5)
	subtract=PeekInt(bank,10)
	multiply=PeekInt(bank,15)
	divide=PeekInt(bank,20)
	value1=PeekInt(bank,25)
	value2=PeekInt(bank,30)
 Repeat 
	If EventID()=$401
		Select EventSource()
			Case plus 
			Notify("Answer:"+TextAreaText(value1)+TextAreaText(value2)+"")
			Case subtract
			Notify("Answer:"+TextAreaText(value1)-TextAreaText(value2)+"")
			Case multiply
			Notify("Answer:"+TextAreaText(value1)*TextAreaText(value2)+"")
			Case divide
			Notify("Answer:"+TextAreaText(value1)/TextAreaText(value2)+"")
				Select WaitEvent()
					Case $803
					Notify("Bye bye, 'till next time")
					Delay 500
					End
				End Select  
		End Select
	EndIf
 Forever
End Function