修改修改组分类原有视图选中为空报错bug

OTSPartA_STDEditor/UI/STDRuleslist.cs

@@ -814,7 +814,7 @@ namespace OTSPartA_STDEditor
             {
                 return;
             }
-            if (treeView_G.SelectedNode.Level == null)
+            if (treeView_G.SelectedNode == null)
             {
                 return;
             }