void (@NlsSafe @Nullable String relativeSourceRootPath) { JComboBox<?> comboBox = getComboBox(); if (relativeSourceRootPath != null && comboBox.getSelectedItem() == DirectoryChooser.ItemWrapper.NULL) { comboBox.setToolTipText(relativeSourceRootPath); } else { comboBox.setToolTipText(null); } }