added a fix on window versions

git-svn-id: http://svn.d4science-ii.research-infrastructures.eu/gcube/trunk/portlets/user/workspace@144200 82a268e6-3cf1-43bd-a215-b396298e98cf

src/main/java/org/gcube/portlets/user/workspace/client/view/versioning/VersioningInfoContainer.java

@@ -225,18 +225,21 @@ public class VersioningInfoContainer extends LayoutContainer {
 			@Override
 			public void componentSelected(ButtonEvent ce) {
 
-				String msg = "Deleting all older versions of: <br/> - "+ currentVersion.getName()+"." +
-					"<br/>Confirm?";
-				DialogConfirm box = new DialogConfirm(null, "Delete older versions of: "+ currentVersion.getName(), msg);
-				box.getYesButton().addClickHandler(new ClickHandler() {
-
-					@Override
-					public void onClick(ClickEvent event) {
-						AppController.getEventBus().fireEvent(new FileVersioningEvent(WorkspaceVersioningOperation.DELETE_ALL_OLDER_VERSIONS, currentVersion, store.getModels(), windowVersioning));
-					}
-				});
-				box.setModal(true);
-				box.center();
+				if(store.getModels().size()>0){
+
+					String msg = "Deleting all older versions of: <br/> - "+ currentVersion.getName()+"." +
+						"<br/>Confirm?";
+					DialogConfirm box = new DialogConfirm(null, "Delete older versions of: "+ currentVersion.getName(), msg);
+					box.getYesButton().addClickHandler(new ClickHandler() {
+
+						@Override
+						public void onClick(ClickEvent event) {
+							AppController.getEventBus().fireEvent(new FileVersioningEvent(WorkspaceVersioningOperation.DELETE_ALL_OLDER_VERSIONS, currentVersion, store.getModels(), windowVersioning));
+						}
+					});
+					box.setModal(true);
+					box.center();
+				}
 
 			}
 		});