Issue 5006: Switching panels does not correctly set the command line auto-completer

Steps to reproduce

  1. Open Firebug
  2. Switch to the HTML panel, and enable the Console panel through its right-click menu
  3. Click the Show Command Line button.
  4. Type win into the Command Line
    window should appear as a completion.
  5. Clear its contents, and switch to the Console panel
  6. Open the Command Editor
  7. Switch to the HTML panel
  8. Type win into the Command Line again
    Completions should still appear.