Currently Zotero doesn't support assign CollectionTreeRow that is not in the CollectionTree (left side bar) to ItemPane.
When selecting an item in the item pane, Zotero check firstly which CollectionTreeRow is selected in the collectionsView, and returns directly when there is no selection in the collectionsView. Thus, the code of changing the content in the right side bar is not running.
Currently Zotero doesn't support assign CollectionTreeRow that is not in the CollectionTree (left side bar) to ItemPane.
When selecting an item in the item pane, Zotero check firstly which CollectionTreeRow is selected in the collectionsView, and returns directly when there is no selection in the collectionsView. Thus, the code of changing the content in the right side bar is not running.