The button is displayed at directory level. If you are in a directory that has already been added, the button is displayed.
Click on the button to enter the selected directory as a filter for the directory to be searched in the search bar. If necessary, enter any other search terms or use other search methods. Then start the search.
-> The search results are displayed.
The selected directory is entered under Recently searched directories so that you can use it as a filter for new searches at any time.