title: Possible obscure causes for Abstract Error in Delphi?
body: <p>In a Delphi 7 project we installed FastMM. Soon after that we noticed one of the forms started to issue Abstract Error message on close. I have debugged this extensively and I can't find the reason so far. The usual reason for this error message doesn't seem to apply here. The application doesn't define abstract classes. I also searched the form for a possible use of TStrings or something like that. Most importantly, we didn't (well, we think we didn't) make any changes to this form. It just broke. </p>
  
  <ol>
  <li>Are there some other possible causes for this error besides trying to call unimplemented method?</li>
  <li>Is there some possibilty that FastMM has enabled some obscure bug in the application, that remained hidden until now?</li>
  </ol>
  
  <p>If the answer to these questions is no, then I'll just continue to search for an unimplemented method call, relieved that I am not missing something else.</p>