this is the default, and as such it should be given a higher priority

core/src/main/java/hudson/slaves/RetentionStrategy.java

@@ -140,7 +140,7 @@ public abstract class RetentionStrategy<T extends Computer> extends AbstractDesc
             return 1;
         }
 
-        @Extension
+        @Extension(ordinal=100)
         public static class DescriptorImpl extends Descriptor<RetentionStrategy<?>> {
             public String getDisplayName() {
                 return Messages.RetentionStrategy_Always_displayName();