Selecting items

Some of Whorld's dialogs allow multiple items to be selected at once. The interface is common to all Windows applications, but it's described here anyway.

Single itemLeft-click it.
Contiguous groupLeft-click the first item, and then Shift+left-click the last item. Shift+left-click can also expand or trim an existing selection.
Non-contiguous groupCtrl+left-click each item. To remove a item from the selection, Ctrl+left-click it again.
All itemsLeft-click any item, and press Ctrl+A.