Fixed closing navigation menu on clicking separator

app/src/main/java/eu/faircode/email/ActivityView.java

@@ -177,6 +177,8 @@ public class ActivityView extends ActivityBilling implements FragmentManager.OnB
             public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                 DrawerItem item = (DrawerItem) parent.getAdapter().getItem(position);
                 switch (item.getId()) {
+                    case 0: // separator
+                        return;
                     case -1:
                         onMenuFolders((long) item.getData());
                         break;
@@ -1124,6 +1126,7 @@ public class ActivityView extends ActivityBilling implements FragmentManager.OnB
         private Object data;
 
         DrawerItem(int layout) {
+            this.id = 0;
             this.layout = layout;
         }