When working through the Sandbox Activity entitled "Part 2: Deploying full-stack JavaScript applications to the Developer Sandbox for Red Hat OpenShift" (Full-stack JavaScript sandbox activity part 2 - Red Hat Developer), the user is instructed to configure the environment variables — Figure 3 in the activity.

When I clicked the Save button to submit the edited Deployment, I received the following error:

Alert box:

An error occurred
Error "Invalid value: v1.LabelSelector{MatchLabels:map[string]string{"app":"urlshortener","deployment":"urlshortener"}, MatchEpressions:[]v1.LabelSelectorRequirement(nil)}: field is immutable" for field "spec.selector".