(mis)behaviour of getOpenFile

I am trying to use the getOpenFile widget (Mastering Perl/Tk page 568 – First Edition).  Whilst this is perfectly OK when there are 3000 files in a directory I do not get a list of files (even when leaving the application running for a matter of minutes) to select from when there are 6000 files in the directory.  Looking at the task manager I find that Perl.exe is running and using about 70% of the CPU time and that the memory used in lower than that available.  I can view the directory using the Windows Explorer.  Is there a fundamental problem and/or how can I make the widget work quicker?

 

Best regards

 

Henry Merryweather