I found Activity Plus plugin has conflict with Hierarchy plugin. When I post photos with Activity Plus plugin, there are often failures happened. After research, I found the reason:
When Activity Plus post the photos to the current group, browser will locate to the root group. If current user doesn't has the permission for the root group, the photo post is failed.
I tried to solve the bug, but I don't know why and how Activity Plus locate the root group. I find below code trigger the location behavior:
In line 1204 of fileuploader.js:
Is there anyone tell me why it happened?