Some users use the "All documents" view as their regular view. When doing a search with the upper right box, a new tab is open with the search results. The view that is used to display the search result is the "($All)" view. When some conditions are met, going back to the "All documents" view and doing some actions (Reply, Forward, Delete), these actions are done on the selected documents from the search results, not the actual documents selected by the user. This is confusing and users don't understand why reply/forward/delete is not done on the right documents.
So the search (upper right box) should not be done on the "($All)" view. A new hidden view should be created.
As a workaround, I modified the outline to point the "All documents" entry to a copy of the "($All)" view.