Where is my empty storage gone?
In the moment the last bottle of a non-empty storage is removed the storage's state changes to empty. Therefore the storage now moves to the list of empty storages. To see the list of empty storages simply select the tab "Empty" which is the rightmost one. If you cannot see it because your display is too tall just drag the tabs to the left to see the remaining tabs. In case you cannot see the "Empty" tab you might have selected the preference "Don't show empty storages".