title: Why is "Use environment variable" option disabled/grayed out in SSIS2012 catalog configuration?
body: <p>This may sound like an easy question but the answers on the net all point to the basics of setting up an environment and referencing it in the project/package.</p>
  
  <p>The scenario that I have encountered was never mentioned anywhere so I thought it would be good to document the behaviour here.</p>
  
  <p>Below is the steps to reproduce the problem:<br>
  1. Create a new package: <code>Package1.dtsx</code><br>
  2. Create a new (package) parameter: <code>Test, Int32, Required</code><br>
  3. Deploy the project.<br>
  4. Goto Integration Services Catalogs and navigate to the package.<br>
  5. Right click on the package and then Configure...<br>
  6. Click on "..." next to the package parameter <code>Test</code><br>
  7. You will see that <code>"Use environment variable"</code> option is disabled/grayed out.</p>
  
  <p><img src="https://i.stack.imgur.com/MOwvY.png" alt="Set Parameter Value"></p>
  
  <p><strong>Why is that?</strong></p>