fix: OPTIC-353: Fix null errors when switching from task detail to settings

src/LabelStudio.js

@@ -79,6 +79,8 @@ export class LabelStudio {
     };
 
     const clearRenderedApp = () => {
+      if (!rootElement.childNodes?.length) return;
+
       const childNodes = [...rootElement.childNodes];
       // cleanDomAfterReact needs this key to be sure that cleaning affects only current react subtree
       const reactKey = findReactKey(childNodes[0]);

src/regions/VideoRegion.js

@@ -1,4 +1,4 @@
-import { types } from 'mobx-state-tree';
+import { getRoot, types } from 'mobx-state-tree';
 
 import { guidGenerator } from '../core/Helpers';
 import { AreaMixin } from '../mixins/AreaMixin';
@@ -34,7 +34,7 @@ const Model = types
     },
 
     get annotation() {
-      return self.object.annotation;
+      return getRoot(self).annotationStore.selected;
     },
 
     getShape() {

src/stores/AppStore.js

@@ -875,12 +875,14 @@ export default types
         const children = [];
 
         walk(self, (node) => {
-          if (!isRoot(node) && getParent(node) === self) children.push(node);
+          if (!isRoot(node) && getParent(node) === self) {
+            children.push(node);
+          }
         });
 
         let node;
 
-        while ((node = children.shift())) {
+        while (node = children.shift()) {
           try {
             destroy(node);
           } catch (e) {