Refactor inventorySelect to build it hierarchically

internal/ui/driver.go

@@ -15,10 +15,6 @@ import (
 )
 
 func init() {
-	// These menu types don't need driving, so we can ignore them
-	registerBuilder(menus.TypeMenu, nil)     // Menus are just containers
-	registerBuilder(menus.TypeDragMenu, nil) // Menus are just containers
-
 	// FIXME: these need implementing
 
 	// Needed for Keyboard.mnu (main -> options -> keyboard)
@@ -79,6 +75,10 @@ func noChildren(f func(d *Driver, r *menus.Record) error) builderFunc {
 	}
 }
 
+func ownedByMenu(d *Driver, r *menus.Record) ([]*menus.Record, error) {
+	return nil, fmt.Errorf("This record should be handled by a menu: %v:%v (%#+v)", r.Menu.Name, r.Path(), r)
+}
+
 func registerBuilder(t menus.MenuType, f builderFunc) {
 	if _, ok := widgetBuilders[t]; ok {
 		panic(fmt.Sprintf("A builder for menu type %v already exists", t))