Testopia

In Testopia 1.2, in addition to turning on the parameter, you need to make sure you have permissions in the test plan.

Find the plan the run is in. If you are an administrator of the test plan, or an admin in Bugzilla, you can edit the permissions by clicking the link "Edit Access Controls". If not, ask the plan administrator (usually the author) to add you to the test plan with delete rights.

Greg