Title: Lock refreshing of some window
This example shows, how to lock refreshing of Edit component. Use LockWindowUpdate for this.
When you will press button1 and, after that, button3, then you won't see 'Hello' string in Edit component.
procedure TForm1.Button1Click(Sender: TObject);
begin
LockWindowUpdate(Edit1.Handle);
end;
procedure TForm1.Button3Click(Sender: TObject);
begin
Edit1.Text:='Hello';
end;
procedure TForm1.Button2Click(Sender: TObject);
begin
LockWindowUpdate(0);
end;