Observed:
The form.Cls() is useful to cancel text or graphic operations.
But Cls() is implemented with window messages,
in this way a lockscreen=.T. it stops the elaboration of the messages,
and therefore Cls() is performed after LockScreen =.F.
with the result to cancel the new operations done on the VFP buffer.
Not badly.


- Run and move the mouse
- check unckeck

WITH CREATEOBJECT("form1")
	.Show(1)
ENDWITH

DEFINE CLASS form1 AS form
	
	ADD OBJECT Check1 AS CheckBox with;
	Value = .F.;
,       Caption    = "in Lockscreen"

	PROCEDURE MouseMove(a,b,x,y)
		thisform.LockScreen = thisform.check1.Value

		thisform.Cls

		thisform.Circle(50,x,y)
		thisform.Print("some text",x-30,y-30)
		
		thisform.LockScreen = .F.
	ENDPROC

ENDDEFINE