title: Simulink: How to resolve "Invalid setting for output port dimensions of '*/Bus Creator'. The dimensions are being set to 1." error
body: <p>I'm running into the following issue in a simulink model (R2012b, 64bit):</p>
  <ul>
  <li><p>in a subsystem, three scalar signals enter a bus creator</p>
  </li>
  <li><p>the output of the bus creator is connected to one of the subsystem's output ports. The size of the output port is set to -1, i.e. inherits its size from the incoming signal</p>
  </li>
  <li><p>The subsystem is embedded in another subsystem</p>
  </li>
  <li><p>When the model is executed, the following error message appears:</p>
  </li>
  </ul>
  <p><strong>Invalid setting for output port dimensions of 'lonsys/A\C 1 DOF/Simple longitudinal attitude system/Bus Creator'. The dimensions are being set to 1. This is not valid because the total number of input and output elements are not the same</strong></p>
  <p>From looking at the bus creator that raises the error, it is not at all clear what is going wrong.</p>
  <p>Ideas?</p>