From my point of view does not make sense to allow users to switch deploy project from JBoss app to for example Ruby and vice versa. Furthermore when tried to deploy Ruby app instead of JBoss a NPE was thrown:
java.lang.NullPointerException at org.jboss.tools.openshift.express.internal.core.behaviour.ExpressPublishMethod.publishModule(ExpressPublishMethod.java:122) at org.jboss.ide.eclipse.as.core.server.internal.DeployableServerBehavior.publishModule(DeployableServerBehavior.java:119) at org.eclipse.wst.server.core.model.ServerBehaviourDelegate.publishModule(ServerBehaviourDelegate.java:1046) at org.eclipse.wst.server.core.model.ServerBehaviourDelegate.publishModules(ServerBehaviourDelegate.java:1138) at org.eclipse.wst.server.core.model.ServerBehaviourDelegate.publish(ServerBehaviourDelegate.java:955) at org.jboss.tools.openshift.express.internal.core.behaviour.ExpressBehaviour.publish(ExpressBehaviour.java:27) at org.eclipse.wst.server.core.model.ServerBehaviourDelegate.publish(ServerBehaviourDelegate.java:774) at org.jboss.tools.openshift.express.internal.core.behaviour.ExpressBehaviour.publish(ExpressBehaviour.java:34) at org.eclipse.wst.server.core.internal.Server.publishImpl(Server.java:3087) at org.eclipse.wst.server.core.internal.Server$PublishJob.run(Server.java:345) at org.eclipse.core.internal.jobs.Worker.run(Worker.java:54)