LablTk: listboxes

How to create a simple listbox? Parameter selectmode specifies the selection mode. Here are the possible values: `Single   Only one element may be selected at a time. `Multiple   Several elements may be selected. Clicking on a non-selected element makes it selected. Clicking on a selected element makes it non selected. `Browse   Only one element may be selected at a time. Moving the mouse while keeping pressed the left button of the mouse causes the selection to be moved at the same time. `Extended   The user may select several elements. Clicking on a selected element unselects all other elements. Moving the mouse selects all encountered elements. Clicking on a non selected element while pressing Shift selects all elements between the last selected element and the current element.

You have to use function Listbox.insert to insert a list of elements into a Listbox widget.
Its parameter index specifies at which position the insertion will start:

`Num n		Position in the list: an integer.
`End		End of list
`Active		Position of active element
`Anchor
`Atxy of (x,y)		Index corresponding to the position (x,y) in pixels

How to select an item in a listbox? Method Listbox.curselection the list of selected elements, and an empty list if no element is currently selected. Method Listbox.get the element whose index is given as a parameter (with type `Num of int).

After selecting a composer and clicking on "Show selected composer":