title: Netbeans Swing UI designer - what does the hazard icon mean?
body: <p>I'm working in the Design view of a Swing application and occassionally I see a small hazard warning symbol appear in the top corner of a component.</p>
  
  <p>I assumed this was something to do with visibility overlap or similar but having adjusted things I can't match a guess against anything credible. Unfortunately it doesn't have a tool-tip and does not react to any mouse clicks.</p>
  
  <p>Any ideas? Google does not seem to suggest anything either.</p>