Please make 'checkLastModificationDate' check optional (checkbox -> optionalBlock). Now it undisableable.

My situation was following:
Using URLTrigger to retrieve change information from artifact hosted by Nexus Sonatype (ex. http://<addr>/repositories/public/<myproject>/pom.xml). I have option to check 'timestamp' element in the pom.xml, but it never happens - lastModificationDate was always new (maybe it's Sonatype bug, i dont know). Undisebleability of this option cause my project rebuild in infinite loop (because lastModification is always new).

Currently i make a local change in config.jelly and now i works good.