title: Android 9 Patch tool: What is the new layout bounds feature?
body: <p>I've updated r20 of the Android SDK and started the 9 Patch tool. </p>
  
  <p>There seems to be a new feature - Holding Control and clicking adds layout bounds which are referred to as red pixels. </p>
  
  <p>I've taken a look at the <a href="http://developer.android.com/tools/help/draw9patch.html">documentation</a> but it seems out of date. </p>
  
  <p>My question is, what are layout bounds used for and what is the best way to use them? </p>
  
  <p>Thanks. </p>