title: C# sometimes the first command running after the second command
body: <p>Sometimes when I set a PictureBox visible to false (for example) or set the text of some TextBox and then write "System.Threading.Thread.Sleep(X)" (for example) the first command carried out just after the sleep command.</p>
  
  <p>How can it to be?
  Are there some commands that work in the background?</p>
  
  <p>it's make me confused.
  It makes a lot of bugs in my projects.</p>