Bugfix for vendored loadingSelector function (#1140)

Author: tcbegley

src/private/util.js

@@ -82,8 +82,9 @@ const getLoadingState = () => {
 // vendored from dcc.Loading
 const loadingSelector = (componentPath, targetComponents) => state => {
   let stringPath = JSON.stringify(componentPath);
-  // Remove the last ] for easy match
-  stringPath = stringPath.substring(0, stringPath.length - 1);
+  // Remove the last ] for easy match and add `,` to make sure only children
+  // trigger the loading. See issue: https://github.com/plotly/dash/issues/3276
+  stringPath = stringPath.substring(0, stringPath.length - 1) + ',';
   const loadingChildren = toPairs(state.loading).reduce((acc, [path, load]) => {
     if (path.startsWith(stringPath) && load.length) {
       if (