feat: #258 Loosing registered tree affecting drag and drop between different trees. (#439)

* 258: Using the updater function for setting new value for trees to avoid an issue in dragging items between trees.
Drag and drop between trees was not working if the target tree was unmounted and mounted before the drag operation.

* 258: updated release notes

* fix: linter fix

---------

Co-authored-by: Lukas Bach <contact@lukasbach.com>

Author: as666499

next-release-notes.md

@@ -4,6 +4,7 @@
 ### Features
 
 ### Bug Fixes and Improvements
+- Fixes an issue where drag and drop between trees was not working after remount of the target tree(#258)
 
 ### Other Changes
 -->

packages/core/src/controlledEnvironment/useControlledTreeEnvironmentProps.ts

@@ -88,8 +88,11 @@ export const useControlledTreeEnvironmentProps = ({
   const unregisterTree = useCallback(
     treeId => {
       onUnregisterTree?.(trees[treeId]);
-      delete trees[treeId];
-      setTrees(trees);
+      setTrees(trees => {
+        const newTrees = { ...trees };
+        delete newTrees[treeId];
+        return newTrees;
+      });
     },
     [onUnregisterTree, trees]
   );