show counterexample found on selected hypotheses

de.prob.eventb.disprover.core/src/de/prob/eventb/disprover/core/DisproverReasoner.java

@@ -4,6 +4,9 @@ import java.util.HashSet;
 import java.util.Set;
 
 import org.eclipse.core.runtime.Status;
+import org.eclipse.jface.dialogs.MessageDialog;
+import org.eclipse.swt.widgets.Shell;
+import org.eclipse.ui.PlatformUI;
 import org.eventb.core.IEventBProject;
 import org.eventb.core.IPOSequent;
 import org.eventb.core.ast.Predicate;
@@ -183,6 +186,15 @@ public class DisproverReasoner implements IReasoner {
 			System.out.println(sequent.toString()
 					+ ": Counter-Example for selected hypotheses found.");
 
+			Shell activeShell = PlatformUI.getWorkbench()
+					.getActiveWorkbenchWindow().getShell();
+			MessageDialog
+					.openWarning(
+							activeShell,
+							"Goal not provable",
+							"ProB found a Counter-Example for the selected Hypotheses, Goal not provable from selected Hypotheses but may be provable with all Hypotheses.\n"
+									+ counterExample.toString());
+
 			return ProverFactory
 					.reasonerFailure(
 							this,