[#1417] Plug-in editor: Runtime tab should show selected package

The simplest solution would be to use the section description

ui/org.eclipse.pde.ui/src/org/eclipse/pde/internal/ui/editor/plugin/ExportPackageVisibilitySection.java

@@ -19,7 +19,11 @@
 import static org.eclipse.swt.events.SelectionListener.widgetSelectedAdapter;
 
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.List;
+import java.util.Objects;
+import java.util.Optional;
+import java.util.stream.Collectors;
 
 import org.eclipse.jface.action.Action;
 import org.eclipse.jface.action.IMenuManager;
@@ -373,6 +377,15 @@ private void update(ExportPackageObject[] objects) {
 		getTablePart().setButtonEnabled(1, fInternalButton.getSelection() && isEditable());
 		fFriendViewer.setInput(object);
 		fBlockChanges = false;
+		getSection().setDescription(Optional.ofNullable(objects).map(this::description)
+				.orElse(PDEUIMessages.ExportPackageVisibilitySection_default));
+	}
+
+	private String description(ExportPackageObject[] packages) {
+		return Arrays.stream(packages)//
+				.filter(Objects::nonNull)//
+				.map(ExportPackageObject::getName)
+				.collect(Collectors.joining(", ")); //$NON-NLS-1$
 	}
 
 	private BundleInputContext getBundleContext() {