link to JBIDE-10514 , a UI is required for this setting.

1. Create a new application in wizard and allow to create a new project in the workspace
2. Fix all the bugs so that it compiles (delete modules.jsp, add java version 1.6 to pom.xml, reload project configuration)
3. Modify all your build stuff so the project does NOT deploy to root
4. Change your context root to match what your setting is in the build
5. Right click the project and select Run as... + Run on server
6. Choose associated openshift server
7. Result - No page found due to the incorrect URL. It's still using root instead of your new custom context root

A UI is required for this setting