Kid 0 - XuiListButton
"Selection" callback when XuiList item selected
v0 : item - 0 is topmost item
XuiListButton grids display a text string on the XuiListButton grid, and a list of items in an XuiList grid window that toggles up and down when the XuiListButton is selected.
XuiListButton grids generate Selection callback messages when the user selects any item from the XuiList grid.
The XuiListButton grid manages the XuiList window, so the text on the XuiListButton is its TextString property and the XuiList items are the TextArray property of the XuiListButton.
