diff --git a/client/src/js/appDataAdmin.js b/client/src/js/appDataAdmin.js
index e699cd4b..432c1ff4 100644
--- a/client/src/js/appDataAdmin.js
+++ b/client/src/js/appDataAdmin.js
@@ -1,4 +1,5 @@
 async function addAppDataAdmin( params ) {
+  let detailBodyWrapEl
   try {
     let { treePath } = params
     const tab = Ext.getCmp('main-tab-panel').getItem('appdata-admin-tab')
@@ -250,6 +251,8 @@ async function addAppDataAdmin( params ) {
     })
     thisTab.show()
 
+    detailBodyWrapEl = detailJson.getEl().child('.x-panel-bwrap')
+    detailBodyWrapEl.mask('Getting data...')
     const detailResponseText = (await getDetail()).response.responseText //used by downloadBlob
     const detailTree = JsonView.createTree(JSON.parse(detailResponseText))
     // adjust for rendering
@@ -258,10 +261,12 @@ async function addAppDataAdmin( params ) {
     detailTree.isExpanded = true
     detailTree.children[0].isExpanded = true
 
-    const el = detailJson.body
-    JsonView.render(detailTree, el)
+    JsonView.render(detailTree, detailJson.body)
   }
   catch (e) {
     SM.Error.handleError(e)
   }
+  finally {
+    detailBodyWrapEl.unmask()
+  }
 }
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