If you open and close the same window many times does the used memory keep growing? If not then there's no leak in that part. It's next to impossible to prove a program has no leaks (especialy in Perl), but if you run it for long and do not see a problem I don't think it's necessary to care much :-)
As someone (sorry don't remember who) has in his/her signature: Worry only about the things you have to implement.
Always code as if the guy who ends up maintaining your code
will be a violent psychopath who knows where you live.
-- Rick Osborne
Edit by castaway: Closed small tag in signature