title: Function blocks and subsystems open in a new window
body: <p>I use Simulink with many Subsystems. If I open a Block, a new window will appear. 
  That's quit annoying, if you open 10 blocks. </p>
  
  <p>I know there must be a possibility to change that behavior. So that the new block is displayed in the existing window. </p>
  
  <p>But how can I configure that?</p>