Changes to "Issues" Template

I started with the "Issues" template and am customizing it to fit particular
needs. I have changed the "Due Date" to "Completed Date". I have managed to
change almost everything associated with this field. However, I am having
one problem. The reports for Open Issues have all due dates that are past
due showing as red. I know I am overlooking the simplest thing, but I cannot
for the life of me figure out where it is. Any help would be appreciated.
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Thank you for your time and assistance!

Elizabeth