修改样式

src/css/knowledgeMap.less

@@ -123,6 +123,7 @@
                     border-radius: 4px 0 0 4px;
                     box-sizing: border-box;
                     overflow-y: auto;
+                    z-index:2;
                     li{
                         height: 40px;
                         line-height: 40px;