Only use header loader when updating navigation tree

src/scenes/DocumentScene/DocumentScene.js

@@ -116,6 +116,7 @@ class DocumentScene extends React.Component {
         title={ title }
         titleText={ titleText }
         actions={ actions }
+        loading={ this.store.updatingStructure }
       >
         { this.store.isFetching ? (
           <CenteredContent>

src/scenes/DocumentScene/DocumentSceneStore.js

@@ -7,6 +7,7 @@ class DocumentSceneStore {
   @observable document;
 
   @observable isFetching = true;
+  @observable updatingStructure = false;
   @observable isDeleting;
 
   /* Computed */
@@ -52,7 +53,7 @@ class DocumentSceneStore {
       return true;
     }
 
-    this.isFetching = true;
+    this.updatingStructure = true;
 
     try {
       const res = await client.post('/atlases.updateNavigationTree', {
@@ -66,7 +67,7 @@ class DocumentSceneStore {
     } catch (e) {
       console.error("Something went wrong");
     }
-    this.isFetching = false;
+    this.updatingStructure = false;
   }
 };