/* sets or hides fields depending on which tab is shown */
public void setVisibleComponents(nonHumanMgt.SelType sType) {
boolean catTab = (sType == nonHumanMgt.SelType.category);
// these only appear on the resources tab
cbbCategory.setVisible(!catTab);
lblSubCategory.setVisible(!catTab);
cbbSubCategory.setVisible(!catTab);
// these only appear on the categories tab
lblMembers.setVisible(catTab);
cbbMembers.setVisible(catTab);
lbxSubCatItems.setVisible(catTab);
btnAddSubCat.setVisible(catTab);
btnRemoveSubCat.setVisible(catTab);
// nullify lists
if (catTab) {
cbbCategory.setItems(null);
cbbSubCategory.setItems(null);
} else lbxSubCatItems.setItems(null);
}